Gui: Use auto and range-based for (#7481)

* On lines where the variable type is obvious from inspection, avoid repeating the type using auto. 
* When possible use a ranged for loop instead of begin() and end() iterators

src/Gui/TaskView/TaskWatcher.cpp

@@ -82,7 +82,7 @@ TaskWatcherCommands::TaskWatcherCommands(const char* Filter,const char* commands
 {
     if (commands) {
         CommandManager &mgr = Gui::Application::Instance->commandManager();
-        Gui::TaskView::TaskBox *tb = new Gui::TaskView::TaskBox
+        auto tb = new Gui::TaskView::TaskBox
             (BitmapFactory().pixmap(pixmap), tr(name), true, nullptr);
 
         for (const char** i=commands;*i;i++) {