Improve GDScript Editor and Improve latency

Improvements:
- GDScript Highlighter is faster by 25% as keys are smaller (hashes instead of strings)
- Removes message queue from _apply_settings_change to allow resize to work correctly
- Some performance fixes are pending still

Note: this resolves the code editor behaving badly when resizing in debug builds

editor/code_editor.h

@@ -162,8 +162,6 @@ class CodeTextEditor : public VBoxContainer {
 	int error_line;
 	int error_column;
 
-	bool settings_changed = false;
-
 	void _on_settings_change();
 	void _apply_settings_change();