Enable the script editor line length guideline by default

Now that the GDScript style guide has an official recommendation,
it makes sense to enable the line length guideline by default.

editor/editor_settings.cpp

@@ -456,7 +456,7 @@ void EditorSettings::_load_defaults(Ref<ConfigFile> p_extra_config) {
 	_initial_set("text_editor/appearance/show_info_gutter", true);
 	_initial_set("text_editor/appearance/code_folding", true);
 	_initial_set("text_editor/appearance/word_wrap", false);
-	_initial_set("text_editor/appearance/show_line_length_guideline", false);
+	_initial_set("text_editor/appearance/show_line_length_guideline", true);
 	_initial_set("text_editor/appearance/line_length_guideline_column", 80);
 	hints["text_editor/appearance/line_length_guideline_column"] = PropertyInfo(Variant::INT, "text_editor/appearance/line_length_guideline_column", PROPERTY_HINT_RANGE, "20, 160, 1");