Improve error message when _EDITOR_GET fails

Author: timothyqiu

editor/settings/editor_settings.cpp

@@ -1514,7 +1514,8 @@ Variant _EDITOR_DEF(const String &p_setting, const Variant &p_default, bool p_re
 }
 
 Variant _EDITOR_GET(const String &p_setting) {
-	ERR_FAIL_COND_V(!EditorSettings::get_singleton() || !EditorSettings::get_singleton()->has_setting(p_setting), Variant());
+	ERR_FAIL_NULL_V_MSG(EditorSettings::get_singleton(), Variant(), vformat(R"(EditorSettings not instantiated yet when getting setting "%s".)", p_setting));
+	ERR_FAIL_COND_V_MSG(!EditorSettings::get_singleton()->has_setting(p_setting), Variant(), vformat(R"(Editor setting "%s" does not exist.)", p_setting));
 	return EditorSettings::get_singleton()->get_setting(p_setting);
 }