[clang-tools-extra] Add support for renaming objc methods, even those with multiple selector pieces (PR #76466)

[Alex Hoppen via cfe-commits]

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ahoppen wrote:

I think we could also include my tests from https://github.com/llvm/llvm-project/pull/78872/files#diff-26ff7c74af8a1d882abbad43625d3cd4bf8d024ef5c7064993f5ede3eec8752eR834

More tests never hurt.

https://github.com/llvm/llvm-project/pull/76466