update mappings of control flow keywords

All control flow keywords are now mapped to either Keyword, Statement or
Conditional. Previously some of them would be mapped to Special, PreProc
or Macro.

As a reference I used the builtin syntax highlighting from neovim for
the following languages that have similar control flow keywords to Zig:

- Rust:
  - Keyword: return break continue
  - Conditional: match if else
  - Repeat: loop while (actually maps to Conditional)
- C
  - Statement: goto break return continue asm
  - Conditional: if else switch
  - Repeat: while for do
- C#: Conditional, Repeat
  - Conditional: else if switch
  - Repeat: break continue do for foreach goto return while
- JS
  - Statement: return with await yield
  - Conditional: if else switch break continue
  - Repeat: while for do in of
- Go
  - Statement: defer go goto return break continue fallthrough
  - Conditional: if else switch select
  - Repeat: for range

- Zig (old)
  - Macro: defer errdefer
  - PreProc: asm
  - Special: return break continue
  - Conditional: if else switch
  - Repeat: while for
  - Keyword: and or orelse
- Zig (new)
  - Statement: return break continue asm defer errdefer and or orelse
  - Conditional: if else switch
  - Repeat: while for

The try and catch keywords will be adjusted in a future commit.

Author: Techatrix

syntax/zig.vim

@@ -25,9 +25,9 @@ syntax keyword zigException error
 syntax keyword zigStorageClass
 syntax keyword zigDummyVariable _
 syntax keyword zigKeyword var const fn try test pub comptime
-syntax keyword zigExecution return break continue
-syntax keyword zigMacro defer errdefer nosuspend suspend resume export extern
-syntax keyword zigPreProc addrspace align asm callconv catch inline noalias noinline threadlocal
+syntax keyword zigStatement return break continue asm defer errdefer
+syntax keyword zigMacro nosuspend suspend resume export extern
+syntax keyword zigPreProc addrspace align callconv catch inline noalias noinline threadlocal
 syntax keyword zigBuiltinFn @addrSpaceCast @addWithOverflow @alignCast @alignOf @as @atomicLoad @atomicRmw @atomicStore @bitCast @bitOffsetOf @bitSizeOf @branchHint @breakpoint @mulAdd @byteSwap @bitReverse @offsetOf @call @cDefine @cImport @cInclude @clz @cmpxchgStrong @cmpxchgWeak @compileError @compileLog @constCast @ctz @cUndef @cVaArg @cVaCopy @cVaEnd @cVaStart @disableInstrumentation @disableIntrinsics @divExact @divFloor @divTrunc @embedFile @enumFromInt @errorFromInt @errorName @errorReturnTrace @errorCast @export @extern @field @fieldParentPtr @FieldType @floatCast @floatFromInt @frameAddress @hasDecl @hasField @import @inComptime @intCast @intFromBool @intFromEnum @intFromError @intFromFloat @intFromPtr @max @memcpy @memmove @memset @min @wasmMemorySize @wasmMemoryGrow @mod @mulWithOverflow @panic @popCount @prefetch @ptrCast @ptrFromInt @rem @returnAddress @select @setEvalBranchQuota @setFloatMode @setRuntimeSafety @shlExact @shlWithOverflow @shrExact @shuffle @sizeOf @splat @reduce @src @sqrt @sin @cos @tan @exp @exp2 @log @log2 @log10 @abs @floor @ceil @trunc @round @subWithOverflow @tagName @This @trap @truncate @Type @typeInfo @typeName @TypeOf @unionInit @Vector @volatileCast @workGroupId @workGroupSize @workItemId
 
 syntax match zigType "\v<[iu][1-9]\d*>"
@@ -91,10 +91,10 @@ highlight default link zigNumber Number
 highlight default link zigArrowCharacter zigOperator
 highlight default link zigOperator Operator
 highlight default link zigStructure Structure
-highlight default link zigExecution Special
 highlight default link zigMacro Macro
+highlight default link zigStatement Statement
 highlight default link zigConditional Conditional
-highlight default link zigComparatorWord Keyword
+highlight default link zigComparatorWord zigStatement
 highlight default link zigRepeat Repeat
 highlight default link zigSpecial Special
 highlight default link zigPreProc PreProc