Add subsequence search to tools

Add it to the following searches:
- Create node.
- Scene tree.
- Inspector properties.
- Classes list in help.
- Quick open.

tools/editor/editor_help.cpp

@@ -453,7 +453,7 @@ void EditorHelpIndex::_update_class_list() {
 			String type = E->key();
 
 			while(type != "") {
-				if (type.findn(filter)!=-1) {
+				if (filter.is_subsequence_ofi(type)) {
 
 					if (to_select.empty()) {
 						to_select = type;