patch 9.0.0434: gitignore files are not recognized

Problem:    gitignore files are not recognized.
Solution:   Add patterns for the gitignore filetype. (closes #11102)

Author: ObserverOfTime

runtime/filetype.vim

@@ -721,12 +721,15 @@ au BufNewFile,BufRead .gitmodules,*.git/modules/*/config	setf gitconfig
 if !empty($XDG_CONFIG_HOME)
   au BufNewFile,BufRead $XDG_CONFIG_HOME/git/config		setf gitconfig
   au BufNewFile,BufRead $XDG_CONFIG_HOME/git/attributes		setf gitattributes
+  au BufNewFile,BufRead $XDG_CONFIG_HOME/git/ignore		setf gitignore
 endif
 au BufNewFile,BufRead .gitattributes,*.git/info/attributes	setf gitattributes
-au BufNewFile,BufRead */.config/git/attributes  		setf gitattributes
-au BufNewFile,BufRead */etc/gitattributes  			setf gitattributes
-au BufNewFile,BufRead git-rebase-todo		setf gitrebase
-au BufRead,BufNewFile .gitsendemail.msg.??????	setf gitsendemail
+au BufNewFile,BufRead */.config/git/attributes			setf gitattributes
+au BufNewFile,BufRead */etc/gitattributes			setf gitattributes
+au BufNewFile,BufRead .gitignore,*.git/info/exclude		setf gitignore
+au BufNewFile,BufRead */.config/git/ignore			setf gitignore
+au BufNewFile,BufRead git-rebase-todo				setf gitrebase
+au BufRead,BufNewFile .gitsendemail.msg.??????			setf gitsendemail
 au BufNewFile,BufRead *.git/*
       \ if getline(1) =~# '^\x\{40,\}\>\|^ref: ' |
       \   setf git |

src/testdir/test_filetype.vim

@@ -216,6 +216,7 @@ let s:filename_checks = {
     \ 'gitattributes': ['file.git/info/attributes', '.gitattributes', '/.config/git/attributes', '/etc/gitattributes', '/usr/local/etc/gitattributes', 'some.git/info/attributes'],
     \ 'gitcommit': ['COMMIT_EDITMSG', 'MERGE_MSG', 'TAG_EDITMSG', 'NOTES_EDITMSG', 'EDIT_DESCRIPTION'],
     \ 'gitconfig': ['file.git/config', 'file.git/config.worktree', 'file.git/worktrees/x/config.worktree', '.gitconfig', '.gitmodules', 'file.git/modules//config', '/.config/git/config', '/etc/gitconfig', '/usr/local/etc/gitconfig', '/etc/gitconfig.d/file', 'any/etc/gitconfig.d/file', '/.gitconfig.d/file', 'any/.config/git/config', 'any/.gitconfig.d/file', 'some.git/config', 'some.git/modules/any/config'],
+    \ 'gitignore': ['file.git/info/exclude', '.gitignore', '/.config/git/ignore', 'some.git/info/exclude'],
     \ 'gitolite': ['gitolite.conf', '/gitolite-admin/conf/file', 'any/gitolite-admin/conf/file'],
     \ 'gitrebase': ['git-rebase-todo'],
     \ 'gitsendemail': ['.gitsendemail.msg.xxxxxx'],

src/version.c

@@ -703,6 +703,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    434,
 /**/
     433,
 /**/