[clang] [diagtool] Make the BuiltinDiagnosticsByID table sorted (PR #120321)

[Karl-Johan Karlsson via cfe-commits]

================
@@ -23,28 +23,29 @@ llvm::ArrayRef<DiagnosticRecord> diagtool::getBuiltinDiagnosticsByName() {
   return llvm::ArrayRef(BuiltinDiagnosticsByName);
 }
 
-
 // FIXME: Is it worth having two tables, especially when this one can get
 // out of sync easily?
+// clang-format off
----------------
karka228 wrote:

Add a comment about why we turn off clang-format:
```
// Turn off clang-format, as the order of the includes are important
// to make sure the table is sorted.
```

https://github.com/llvm/llvm-project/pull/120321