[clang] [clang-format]: Add `Custom` to `ShortFunctionStyle`; add new AllowShortFunctionsOnASingleLineOptions for granular setup (PR #134337)

[Owen Pan via cfe-commits]

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@@ -5687,11 +5687,11 @@ bool TokenAnnotator::mustBreakBefore(const AnnotatedLine &Line,
     if (Right.is(tok::r_brace) && Left.is(tok::l_brace) &&
         !Left.Children.empty()) {
       // Support AllowShortFunctionsOnASingleLine for JavaScript.
-      return Style.AllowShortFunctionsOnASingleLine == FormatStyle::SFS_None ||
-             Style.AllowShortFunctionsOnASingleLine == FormatStyle::SFS_Empty ||
+      return (!Style.AllowShortFunctionsOnASingleLine.Inline &&
+              !Style.AllowShortFunctionsOnASingleLine.Other) ||
              (Left.NestingLevel == 0 && Line.Level == 0 &&
-              Style.AllowShortFunctionsOnASingleLine &
-                  FormatStyle::SFS_InlineOnly);
+              Style.AllowShortFunctionsOnASingleLine.Inline &&
+              !Style.AllowShortFunctionsOnASingleLine.Other);
----------------
owenca wrote:

> Since the options are now independent, this part should probably become something like this.
> 
> ```c++
> !(Left.NestingLevel == 0 && Line.Level == 0 ? Style.AllowShortFunctionsOnASingleLine.Other : Style.AllowShortFunctionsOnASingleLine.Inline)
> ```

That seems wrong. See https://github.com/llvm/llvm-project/pull/134337#discussion_r2043562759.

https://github.com/llvm/llvm-project/pull/134337