[clang-tools-extra] Follow style configuration in clangd when inserting missing includes (PR #140594)

[kadir çetinkaya via cfe-commits]

================
@@ -141,16 +143,41 @@ std::vector<Diag> generateMissingIncludeDiagnostics(
          AST.getPreprocessor().getHeaderSearchInfo(), MainFile});
 
     llvm::StringRef HeaderRef{Spelling};
-    bool Angled = HeaderRef.starts_with("<");
+
+    bool IsAngled = false;
----------------
kadircet wrote:

we shouldn't be matching against `HeaderRef`, but instead matching against `ResolvedPath` and only when `SymbolWithMissingInclude.Providers.front().kind() == Physical`

nit:
```cpp
bool Angled = HeaderRef.starts_with("<");
if (SymbolWithMissingInclude.Providers.front().kind() == ..Physical) {
    for (auto &Filter : Angled ? QuotedHeaders : AngledHeaders) {
      if (Filter(ResolvedPath)) {
        Angled = !Angled;
        break;
      }
    }
}
....
std::optional<tooling::Replacement> Replacement = HeaderIncludes.insert(
        HeaderRef.trim("\"<>"), Angled, tooling::IncludeDirective::Include);
```

[logic in the include inserter](https://github.com/llvm/llvm-project/blob/3033f202f6707937cd28c2473479db134993f96f/clang-tools-extra/clangd/Headers.cpp#L307) seem to have the same bug (we should match against paths, not spellings).

https://github.com/llvm/llvm-project/pull/140594