[clang] nonblocking/nonallocating attributes: 2nd pass caller/callee analysis (PR #99656)

[Erich Keane via cfe-commits]

================
@@ -571,6 +571,9 @@ New features
   if class of allocation and deallocation function mismatches.
   `Documentation <https://clang.llvm.org/docs/analyzer/checkers.html#unix-mismatcheddeallocator-c-c>`__.
 
+- Function effects (the ``nonblocking`` and ``nonallocating`` "performance constraint" attributes)
----------------
erichkeane wrote:

I would like some elaboration here, reading this after coming in 'cold' I have no idea what this means.  Also, why double-tilde's?  I think we only use 1 for these?  Or is .rst different enough again...?

https://github.com/llvm/llvm-project/pull/99656