[llvm] [clang] [Sema] Implement support for -Wformat-signedness (PR #74440)

[Aaron Ballman via cfe-commits]

================
@@ -264,6 +264,8 @@ class ArgType {
     /// The conversion specifier and the argument type are compatible. For
     /// instance, "%d" and int.
     Match = 1,
+    /// The conversion specifier and the argument type have different sign
----------------
AaronBallman wrote:

```suggestion
    /// The conversion specifier and the argument type have different sign.
```

https://github.com/llvm/llvm-project/pull/74440