[clang] [Clang][analyzer] add documentation for optin performance padding (padding checker) #73675 (PR #86411)

[Balazs Benics via cfe-commits]

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@@ -804,10 +804,28 @@ Check for performance anti-patterns when using Grand Central Dispatch.
 
 .. _optin-performance-Padding:
 
-optin.performance.Padding
-"""""""""""""""""""""""""
+optin.performance.Padding (PaddingChecker)
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steakhal wrote:

It should be the languages within the parens, that the checker supports.
I think this checker applies for C, C++ and probably even for ObjC as well.

https://github.com/llvm/llvm-project/pull/86411