[clang] [clang-tools-extra] [llvm] [clang] Introduce diagnostics suppression mappings (PR #112517)

[Boaz Brickner via cfe-commits]

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@@ -946,6 +955,27 @@ class DiagnosticsEngine : public RefCountedBase<DiagnosticsEngine> {
     return (Level)Diags->getDiagnosticLevel(DiagID, Loc, *this);
   }
 
+  /// Diagnostic suppression mappings can be used to suppress specific
+  /// diagnostics in specific files.
+  /// Mapping file is expected to be a special case list with sections denoting
+  /// diagnostic groups and `src` entries for globs to suppress. `emit` category
+  /// can be used to disable suppression. Longest glob that matches a filepath
+  /// takes precendence. For example:
----------------
bricknerb wrote:

```suggestion
  /// takes precedence. For example:
```

https://github.com/llvm/llvm-project/pull/112517