ClangTools: Add tr functions to DiagnosticMark

Change-Id: I2563e8ab41d6c0d82be494236972ab528656b260
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/clangtools/diagnosticmark.h

@@ -35,6 +35,7 @@ namespace Internal {
 
 class DiagnosticMark : public TextEditor::TextMark
 {
+    Q_DECLARE_TR_FUNCTIONS(ClangTools::Internal::DiagnosticMark)
 public:
     explicit DiagnosticMark(const Diagnostic &diagnostic);