CppCheck: Tr::tr and code cosmetics

Change-Id: I5e6583984f7dc94e998df3c20840f2ba2e801ab8
Reviewed-by: Alessandro Portale <alessandro.portale@qt.io>

src/plugins/cppcheck/cppchecktrigger.h

@@ -20,16 +20,13 @@ class IDocument;
 class IEditor;
 }
 
-namespace Cppcheck {
-namespace Internal {
+namespace Cppcheck::Internal {
 
 class CppcheckTextMarkManager;
 class CppcheckTool;
 
 class CppcheckTrigger final : public QObject
 {
-    Q_OBJECT
-
 public:
     explicit CppcheckTrigger(CppcheckTextMarkManager &marks, CppcheckTool &tool);
     ~CppcheckTrigger() override;
@@ -51,5 +48,4 @@ private:
     QHash<Utils::FilePath, QDateTime> m_checkedFiles;
 };
 
-} // namespace Internal
-} // namespace Cppcheck
+} // Cppcheck::Internal