[DEADCODE] Add deadcode linter

- Add the experimental
[deacode](https://pkg.go.dev/golang.org/x/tools/internal/cmd/deadcode)
linter to Forgejo.
- To deal with false positives that can happen due to build tags or with code
that's currently only referenced by test code, the output of the tool is
compared against a known-good output.
- This commit doesn't make any attempt to remove any deadcode.

(cherry picked from commit ac462279e9361070326d512fc209b6f148f27865)
(cherry picked from commit b5ea6e85acecb8c02d18d51ec489bb1d329a33ce)
(cherry picked from commit 5915f3643c1939ab09dcac8f9fcb74bd4231a16d)

[CLEANUP] Remove deadcode

- This is deadcode since https://codeberg.org/forgejo/forgejo/pulls/1802
removed the usage of it.

(cherry picked from commit d840b9923e1a7aad7306c6b4d02df771ed0f40f4)
(cherry picked from commit 9442bab6266807141a14a647d3bc383233fc56e9)
(cherry picked from commit 0de9d18863c6af44941c7021548cdb07173ba3c0)
(cherry picked from commit 26abf783746ef29e66eea966160e2f9c139add26)
(cherry picked from commit 05d3a143c3785f3cc5e7f561aa2ad2ba556b55cc)
(cherry picked from commit 4b3d38d)
(cherry picked from commit a726e7198613b330a58c8c6dfc8866c360fbe555)
(cherry picked from commit cb62ae5b9885bcd5c2b6cb60f0e9cce6a991cc3c)
(cherry picked from commit 8195ba06d52fc1a05e9907149bb441b66887870e)
(cherry picked from commit 4570fb591aac0359a36800c8cadcd71613bdc7df)
(cherry picked from commit 1f4d33de2b68c776a305fe38fe6be5ae510ce983)

Author: Gusted

.deadcode-out

@@ -0,0 +1,366 @@
+package "code.gitea.io/gitea/cmd"
+	func NoMainListener
+
+package "code.gitea.io/gitea/cmd/forgejo"
+	func ContextSetNoInit
+	func ContextSetNoExit
+	func ContextSetStderr
+	func ContextGetStderr
+	func ContextSetStdout
+	func ContextSetStdin
+
+package "code.gitea.io/gitea/models"
+	func IsErrUpdateTaskNotExist
+	func (ErrUpdateTaskNotExist).Error
+	func (ErrUpdateTaskNotExist).Unwrap
+	func IsErrSHANotFound
+	func GetYamlFixturesAccess
+
+package "code.gitea.io/gitea/models/actions"
+	func ListUploadedArtifactsByRunID
+	func CountRunJobs
+	func (ScheduleList).GetUserIDs
+	func (ScheduleList).GetRepoIDs
+	func (ScheduleList).LoadTriggerUser
+	func (ScheduleList).LoadRepos
+	func FindSchedules
+	func CountSpecs
+	func GetVariableByID
+
+package "code.gitea.io/gitea/models/asymkey"
+	func HasDeployKey
+
+package "code.gitea.io/gitea/models/auth"
+	func DeleteAuthTokenByID
+	func GetSourceByName
+	func GetWebAuthnCredentialByID
+	func WebAuthnCredentials
+
+package "code.gitea.io/gitea/models/db"
+	func TruncateBeans
+	func InTransaction
+	func DumpTables
+	func Count
+	func FindAndCount
+
+package "code.gitea.io/gitea/models/dbfs"
+	func (*file).renameTo
+	func Create
+	func Rename
+
+package "code.gitea.io/gitea/models/forgejo/semver"
+	func GetVersion
+	func SetVersionString
+	func SetVersion
+
+package "code.gitea.io/gitea/models/forgejo_migrations"
+	func GetCurrentDBVersion
+	func EnsureUpToDate
+
+package "code.gitea.io/gitea/models/git"
+	func RemoveDeletedBranchByID
+
+package "code.gitea.io/gitea/models/issues"
+	func IsErrUnknownDependencyType
+	func (ErrNewIssueInsert).Error
+	func IsErrIssueWasClosed
+	func GetIssueWithAttrsByID
+	func GetRepoIDsForIssuesOptions
+	func GetLabelIDsInOrgByNames
+	func ChangeMilestoneStatus
+	func GetMilestonesByRepoIDs
+	func CountMilestonesByRepoCond
+	func GetMilestonesStatsByRepoCond
+	func IsErrErrPullRequestHeadRepoMissing
+	func (ErrPullRequestHeadRepoMissing).Error
+	func GetPullRequestsByHeadBranch
+	func (ErrIssueStopwatchAlreadyExist).Error
+	func (ErrIssueStopwatchAlreadyExist).Unwrap
+
+package "code.gitea.io/gitea/models/migrations/base"
+	func removeAllWithRetry
+	func newXORMEngine
+	func deleteDB
+	func PrepareTestEnv
+	func MainTest
+
+package "code.gitea.io/gitea/models/organization"
+	func UpdateTeamUnits
+	func (SearchMembersOptions).ToConds
+	func UsersInTeamsCount
+
+package "code.gitea.io/gitea/models/packages/alpine"
+	func GetBranches
+	func GetRepositories
+	func GetArchitectures
+
+package "code.gitea.io/gitea/models/perm/access"
+	func GetRepoWriters
+
+package "code.gitea.io/gitea/models/project"
+	func UpdateBoardSorting
+	func ChangeProjectStatus
+
+package "code.gitea.io/gitea/models/repo"
+	func DeleteAttachmentsByIssue
+	func (*releaseSorter).Len
+	func (*releaseSorter).Less
+	func (*releaseSorter).Swap
+	func SortReleases
+	func (SearchOrderBy).String
+	func IsErrTopicNotExist
+	func (ErrTopicNotExist).Error
+	func (ErrTopicNotExist).Unwrap
+	func GetTopicByName
+	func WatchRepoMode
+
+package "code.gitea.io/gitea/models/system"
+	func DeleteNotice
+
+package "code.gitea.io/gitea/models/unittest"
+	func CheckConsistencyFor
+	func checkForConsistency
+	func GetXORMEngine
+	func OverrideFixtures
+	func InitFixtures
+	func LoadFixtures
+	func Copy
+	func CopyDir
+	func FixturesDir
+	func fatalTestError
+	func InitSettings
+	func MainTest
+	func CreateTestEngine
+	func PrepareTestDatabase
+	func PrepareTestEnv
+	func Cond
+	func OrderBy
+	func LoadBeanIfExists
+	func BeanExists
+	func AssertExistsAndLoadBean
+	func GetCount
+	func AssertNotExistsBean
+	func AssertExistsIf
+	func AssertSuccessfulInsert
+	func AssertCount
+	func AssertInt64InRange
+
+package "code.gitea.io/gitea/models/user"
+	func IsErrPrimaryEmailCannotDelete
+	func (ErrUserInactive).Error
+	func (ErrUserInactive).Unwrap
+	func IsErrExternalLoginUserAlreadyExist
+	func IsErrExternalLoginUserNotExist
+	func IsErrUserSettingIsNotExist
+	func GetUserAllSettings
+	func DeleteUserSetting
+	func GetUserEmailsByNames
+
+package "code.gitea.io/gitea/modules/activitypub"
+	func CurrentTime
+	func containsRequiredHTTPHeaders
+	func NewClient
+	func (*Client).NewRequest
+	func (*Client).Post
+	func GetPrivateKey
+
+package "code.gitea.io/gitea/modules/assetfs"
+	func Bindata
+
+package "code.gitea.io/gitea/modules/auth/password/hash"
+	func (*DummyHasher).HashWithSaltBytes
+	func NewDummyHasher
+
+package "code.gitea.io/gitea/modules/auth/password/pwn"
+	func WithHTTP
+
+package "code.gitea.io/gitea/modules/base"
+	func BasicAuthEncode
+	func IsLetter
+	func SetupGiteaRoot
+
+package "code.gitea.io/gitea/modules/cache"
+	func GetInt
+	func WithNoCacheContext
+	func RemoveContextData
+
+package "code.gitea.io/gitea/modules/charset"
+	func (*BreakWriter).Write
+	func ToUTF8
+	func EscapeControlString
+
+package "code.gitea.io/gitea/modules/context"
+	func GetPrivateContext
+
+package "code.gitea.io/gitea/modules/emoji"
+	func ReplaceCodes
+
+package "code.gitea.io/gitea/modules/eventsource"
+	func (*Event).String
+
+package "code.gitea.io/gitea/modules/git"
+	func AllowLFSFiltersArgs
+	func AddChanges
+	func AddChangesWithArgs
+	func CommitChanges
+	func CommitChangesWithArgs
+	func IsErrExecTimeout
+	func (ErrExecTimeout).Error
+	func (ErrUnsupportedVersion).Error
+	func SetUpdateHook
+	func openRepositoryWithDefaultContext
+	func GetBranchCommitID
+	func IsTagExist
+	func ToEntryMode
+	func (*LimitedReaderCloser).Read
+	func (*LimitedReaderCloser).Close
+
+package "code.gitea.io/gitea/modules/gitgraph"
+	func (*Parser).Reset
+
+package "code.gitea.io/gitea/modules/graceful"
+	func (*Manager).TerminateContext
+	func (*Manager).IsTerminate
+	func (*Manager).Err
+	func (*Manager).Value
+	func (*Manager).Deadline
+
+package "code.gitea.io/gitea/modules/hcaptcha"
+	func WithHTTP
+
+package "code.gitea.io/gitea/modules/json"
+	func (StdJSON).Marshal
+	func (StdJSON).Unmarshal
+	func (StdJSON).NewEncoder
+	func (StdJSON).NewDecoder
+	func (StdJSON).Indent
+
+package "code.gitea.io/gitea/modules/markup"
+	func GetRendererByType
+	func RenderString
+	func IsMarkupFile
+
+package "code.gitea.io/gitea/modules/markup/console"
+	func Render
+	func RenderString
+
+package "code.gitea.io/gitea/modules/markup/markdown"
+	func IsDetails
+	func IsSummary
+	func IsTaskCheckBoxListItem
+	func IsIcon
+	func IsColorPreview
+	func RenderRawString
+
+package "code.gitea.io/gitea/modules/markup/markdown/math"
+	func WithInlineDollarParser
+	func WithBlockDollarParser
+
+package "code.gitea.io/gitea/modules/markup/mdstripper"
+	func StripMarkdown
+
+package "code.gitea.io/gitea/modules/markup/orgmode"
+	func RenderString
+
+package "code.gitea.io/gitea/modules/private"
+	func ActionsRunnerRegister
+
+package "code.gitea.io/gitea/modules/process"
+	func (*Manager).ExecTimeout
+
+package "code.gitea.io/gitea/modules/queue"
+	func newBaseChannelSimple
+	func newBaseChannelUnique
+	func newBaseRedisSimple
+	func newBaseRedisUnique
+	func newWorkerPoolQueueForTest
+
+package "code.gitea.io/gitea/modules/queue/lqinternal"
+	func QueueItemIDBytes
+	func QueueItemKeyBytes
+	func ListLevelQueueKeys
+
+package "code.gitea.io/gitea/modules/setting"
+	func NewConfigProviderFromData
+	func (*GitConfigType).GetOption
+	func InitLoggersForTest
+
+package "code.gitea.io/gitea/modules/storage"
+	func (ErrInvalidConfiguration).Error
+	func IsErrInvalidConfiguration
+
+package "code.gitea.io/gitea/modules/structs"
+	func ParseCreateHook
+	func ParsePushHook
+
+package "code.gitea.io/gitea/modules/sync"
+	func (*StatusTable).Start
+	func (*StatusTable).IsRunning
+
+package "code.gitea.io/gitea/modules/testlogger"
+	func (*testLoggerWriterCloser).pushT
+	func (*testLoggerWriterCloser).Write
+	func (*testLoggerWriterCloser).popT
+	func (*testLoggerWriterCloser).Close
+	func (*testLoggerWriterCloser).Reset
+	func PrintCurrentTest
+	func Printf
+	func NewTestLoggerWriter
+
+package "code.gitea.io/gitea/modules/timeutil"
+	func GetExecutableModTime
+	func Set
+	func Unset
+
+package "code.gitea.io/gitea/modules/translation"
+	func (MockLocale).Language
+	func (MockLocale).Tr
+	func (MockLocale).TrN
+	func (MockLocale).PrettyNumber
+
+package "code.gitea.io/gitea/modules/util/filebuffer"
+	func CreateFromReader
+
+package "code.gitea.io/gitea/modules/web"
+	func RouteMock
+	func RouteMockReset
+
+package "code.gitea.io/gitea/modules/web/middleware"
+	func DeleteLocaleCookie
+
+package "code.gitea.io/gitea/routers/web"
+	func NotFound
+
+package "code.gitea.io/gitea/routers/web/org"
+	func MustEnableProjects
+	func getActionIssues
+	func UpdateIssueProject
+
+package "code.gitea.io/gitea/services/convert"
+	func ToSecret
+
+package "code.gitea.io/gitea/services/forms"
+	func (*DeadlineForm).Validate
+
+package "code.gitea.io/gitea/services/packages/alpine"
+	func BuildAllRepositoryFiles
+
+package "code.gitea.io/gitea/services/pull"
+	func IsCommitStatusContextSuccess
+
+package "code.gitea.io/gitea/services/repository"
+	func GetBranchCommitID
+	func IsErrForkAlreadyExist
+
+package "code.gitea.io/gitea/services/repository/archiver"
+	func ArchiveRepository
+
+package "code.gitea.io/gitea/services/repository/files"
+	func (*ContentType).String
+	func GetFileResponseFromCommit
+	func (*TemporaryUploadRepository).GetLastCommit
+	func (*TemporaryUploadRepository).GetLastCommitByRef
+
+package "code.gitea.io/gitea/services/webhook"
+	func NewNotifier
+

.gitignore

@@ -97,6 +97,7 @@ cpu.out
 /VERSION
 /.air
 /.go-licenses
+/.cur-deadcode-out
 
 # Snapcraft
 /gitea_a*.txt