GDScript completion: Handle quote style ad-hoc to remove editor dependency

`core` and `scene` shouldn't depend on `editor`, so they can't query this style
setting in `get_argument_options`. But we can handle it after the fact in
GDScript's completion code.

Also cleans up a couple extra unused invalid includes in `core`.

core/string/translation.cpp

@@ -35,7 +35,6 @@
 #include "core/os/os.h"
 
 #ifdef TOOLS_ENABLED
-#include "editor/editor_settings.h"
 #include "main/main.h"
 #endif