[clang] [clang] Language to String function (PR #69487)

[Aaron Ballman via cfe-commits]

================
@@ -43,6 +43,7 @@ enum class Language : uint8_t {
   HLSL,
   ///@}
 };
+const char *languageToString(Language L);
----------------
AaronBallman wrote:

```suggestion
StringRef languageToString(Language L);
```

https://github.com/llvm/llvm-project/pull/69487