[clang] [clang-format] Fix extraneous space in block comments ending with **/ (PR #190209)

[Björn Schäpers via cfe-commits]

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@@ -703,6 +700,7 @@ void BreakableBlockComment::insertBreak(unsigned LineIndex, unsigned TailOffset,
                                         WhitespaceManager &Whitespaces) const {
   StringRef Text = Content[LineIndex].substr(TailOffset);
   StringRef Prefix = Decoration;
+  std::string PrefixStorage;
----------------
HazardyKnusperkeks wrote:

```suggestion
  SmallString<128> PrefixStorage;
```

https://github.com/llvm/llvm-project/pull/190209