[clang] Improve clarity of the implicit declaration diagnostic (PR #149314)

[Corentin Jabot via cfe-commits]

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@@ -716,6 +716,10 @@ Improvements to Clang's diagnostics
   Added a new warning in this group for the case where the attribute is missing/implicit on
   an override of a virtual method.
 
+ - Reworded the ``-Wimplicit-function-declaration`` diagnostic to make it more
+   clear that the type selected for the implicit declaration is based on the
+   signature of a standard (C, C++, POSIX) library function. (#GH146924)
+
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cor3ntin wrote:

Can you double check this is aligned as it should?

https://github.com/llvm/llvm-project/pull/149314