[clang-tools-extra] [clang-tidy] 'modernize-use-starts-ends-with': fixed false positives on `find` and `rfind` (PR #129564)

[Nicolas van Kempen via cfe-commits]

https://github.com/nicovank approved this pull request.

I saw you have a pending commit access request -- I'll just let you merge this when you are able to.

https://github.com/llvm/llvm-project/pull/129564