Fix -Wredundant-move and -Wdeprecated-copy warnings (#6663)

* Do not move result at end of function

This makes GCC 9.1.2 happy with the active -Wredundant-move warning.
Indeed, such moving of local variables or local arguments before
returning is unnecessary and prevents the compiler from copy elision
optimization.

Telegram/SourceFiles/chat_helpers/emoji_list_widget.cpp

@@ -427,7 +427,7 @@ object_ptr<TabbedSelector::InnerFooter> EmojiListWidget::createFooter() {
 	Expects(_footer == nullptr);
 	auto result = object_ptr<Footer>(this);
 	_footer = result;
-	return std::move(result);
+	return result;
 }
 
 template <typename Callback>