[clang-tools-extra] [clang-tidy] Extend `performance-prefer-single-char-overloads` to handle ternary operator arguments (PR #187069)

[Yanzuo Liu via cfe-commits]

================
@@ -55,8 +52,7 @@ void PreferSingleCharOverloadsCheck::storeOptions(
 }
 
 void PreferSingleCharOverloadsCheck::registerMatchers(MatchFinder *Finder) {
-  const auto SingleChar =
-      ignoringParenCasts(stringLiteral(hasSize(1)).bind("literal"));
+  const auto SingleChar = expr().bind("literal");
----------------
zwuis wrote:

```
expr(hasType(...))
```

What about this perf improvement?

https://github.com/llvm/llvm-project/pull/187069