[clang] Fix clang to recognize new C23 modifiers %w and %wf when printing (PR #71771)

[via cfe-commits]

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@@ -85,4 +86,31 @@ void z_test(void *p) {
   scanf("%Z", p); // expected-warning{{invalid conversion specifier 'Z'}}
 }
 
+void w_int_test(void) {
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ZijunZhaoCCK wrote:

1. I can't find any tests to verify the print result is correct. Do I miss something?
2. One more test about error handling: `unsupported size` test is missing. Like `printf("%w20d")` should be thrown or raise errors. Should I raise error or any methods to throw the error?

https://github.com/llvm/llvm-project/pull/71771