[clang] [Clang] disallow attributes on void parameters (PR #124920)

[Aaron Ballman via cfe-commits]

================
@@ -3830,6 +3830,8 @@ def warn_type_attribute_wrong_type : Warning<
   "'%0' only applies to %select{function|pointer|"
   "Objective-C object or block pointer}1 types; type here is %2">,
   InGroup<IgnoredAttributes>;
+def warn_attribute_on_void_param: Warning<
+  "attribute %0 cannot be applied to a 'void' parameter">, InGroup<IgnoredAttributes>;
----------------
AaronBallman wrote:

```suggestion
  "attribute %0 cannot be applied to a 'void' parameter">,
  InGroup<IgnoredAttributes>;
```

https://github.com/llvm/llvm-project/pull/124920