[clang] [Clang] add support for C23 'H', 'D', and 'DD' length modifiers (PR #201098)

[Aaron Ballman via cfe-commits]

================
@@ -10706,6 +10706,9 @@ def warn_missing_format_string : Warning<
 def warn_scanf_nonzero_width : Warning<
   "zero field width in scanf format string is unused">,
   InGroup<Format>;
+def warn_format_unsupported_type : Warning<
+  "format specifier requires type %0 which is not supported in this implementation">,
----------------
AaronBallman wrote:

```suggestion
  "format specifies type %0 which is not supported yet">,
```

https://github.com/llvm/llvm-project/pull/201098