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

[Owen Pan via cfe-commits]

================
@@ -5685,11 +5685,27 @@ 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 ||
-             (Left.NestingLevel == 0 && Line.Level == 0 &&
-              Style.AllowShortFunctionsOnASingleLine &
-                  FormatStyle::SFS_InlineOnly);
+      const auto &shortFuncConfig = Style.AllowShortFunctionsOnASingleLine;
+
+      // SFS_All
+      if (shortFuncConfig.isAll())
+        return false;
+
+      // SFS_None and SFS_Empty
+      if (shortFuncConfig == FormatStyle::ShortFunctionStyle{})
+        return true;
+
+      // SFS_Empty
+      if (shortFuncConfig == FormatStyle::ShortFunctionStyle{/*Empty=*/true,
+                                                             /*Inline=*/false,
+                                                             /*Other=*/false}) {
+        return true;
+      }
+
+      if (Left.NestingLevel == 0 && Line.Level == 0)
+        return shortFuncConfig.Inline && !shortFuncConfig.Other;
+
+      return shortFuncConfig.Other;
----------------
owenca wrote:

```suggestion
      if (Left.NestingLevel == 0 && Line.Level == 0)
        return !Style.AllowShortFunctionsOnASingleLine.Other;
      return !Style.AllowShortFunctionsOnASingleLine.Inline;
```

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