[clang] [ASTMatchers] forCallable should not erase binding on success (PR #89657)

[Marco Borgeaud via cfe-commits]

marco-antognini-sonarsource wrote:

> The changes look reasonable to me, but can you also add a release note to clang/docs/ReleaseNotes.rst so that users of AST matchers know about the fix?

Thanks, @AaronBallman, that's a good suggestion. I think I followed the expected format but let me know if you have any suggestions.

https://github.com/llvm/llvm-project/pull/89657