Fix outdated documentation in helloworldplugin

src/plugins/helloworld/helloworldplugin.cpp

@@ -125,7 +125,7 @@ bool HelloWorldPlugin::initialize(const QStringList &arguments, QString *error_m
 }
 
 /*! Notification that all extensions that this plugin depends on have been
-    initialized. The dependencies are defined in the plugins .qwp file.
+    initialized. The dependencies are defined in the plugins .pluginspec file.
 
     Normally this method is used for things that rely on other plugins to have
     added objects to the plugin manager, that implement interfaces that we're