[clang-tools-extra] [clang-tidy] Added check 'bugprone-function-visibility-change' (PR #140086)

[Piotr Zegar via cfe-commits]

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+.. title:: clang-tidy - bugprone-function-visibility-change
+
+bugprone-function-visibility-change
+===================================
+
+Check changes in visibility of C++ member functions in subclasses. The check
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PiotrZSL wrote:

And avoid "The check", documentation is in scope of check.

https://github.com/llvm/llvm-project/pull/140086