[clang-tools-extra] [clang-tidy] Support find for string-like classes in readability-container-contains (PR #157243)

[Nicolas van Kempen via cfe-commits]

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@@ -230,6 +230,10 @@ Changes in existing checks
   <clang-tidy/checks/portability/template-virtual-member-function>` check to
   avoid false positives on pure virtual member functions.
 
+- Fixed false negatives on string and string-like types in
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nicovank wrote:

Sure. Was there official guidelines for this? It wasn't the case [up to the 17 release](https://releases.llvm.org/17.0.1/tools/clang/tools/extra/docs/ReleaseNotes.html).
Since then this became the default (everyone copy-pasting other entries?). I feel like "Improved" is not always the best verb to express the change.

https://github.com/llvm/llvm-project/pull/157243