Use simpler Plugin::initialize() when feasible

Change-Id: I567965d266f20526bda9f823e31a04b354d53fb1
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/macros/macrosplugin.h

@@ -16,7 +16,7 @@ class MacrosPlugin final : public ExtensionSystem::IPlugin
 public:
     ~MacrosPlugin() final;
 
-    bool initialize(const QStringList &arguments, QString *errorMessage) final;
+    void initialize() final;
 
 private:
     class MacrosPluginPrivate *d = nullptr;