[clang] [analyzer] Fix security.VAList false positives with C23 va_start (PR #192024)

[Donát Nagy via cfe-commits]

================
@@ -64,7 +64,7 @@ class VAListChecker : public Checker<check::PreCall, check::PreStmt<VAArgExpr>,
     int ParamIndex;
   };
   static const SmallVector<VAListAccepter, 15> VAListAccepters;
-  static const CallDescription VaStart, VaEnd, VaCopy;
+  static const CallDescription VaStart, VaStartC23, VaEnd, VaCopy;
----------------
NagyDonat wrote:

Good suggestion; @bjosv [here](https://github.com/llvm/llvm-project/blob/f3294c2338d27e2cd411fddcf1afd169d1996ccf/clang/lib/StaticAnalyzer/Checkers/SetgidSetuidOrderChecker.cpp#L40) you can find an example of defining a `CallDescriptionSet` (which will be used as `OtherSetPrivilegeDesc.contains(Call)`.

https://github.com/llvm/llvm-project/pull/192024