### Godot version

4.1.1

### System information

windows 11

### Issue description

When registering a type with class_name and using that class name to declare a variable in code only, autocomplete works as expected anywhere in other nodes/scenes. However, if making a custom scene node that extends a script with the class_name, if that custom scene is instantiated in a different scene, even if the type is specified, it only shows the parent node's functions and not any of the extended functionality. I have made a basic project showing the issue

### Steps to reproduce

I have made a very simple project showing the issue. https://github.com/mmmmmmmmmmmmmmmmmmmdonuts/godot_4_autocomplete_issue essentially, the extended Node scene will only show the custom function when both the type is specified as well as the type afterwards following "as" 
e.g. `@onready var my_class_4: MyClass = $MyClass4 as MyClass`

### Minimal reproduction project

https://github.com/mmmmmmmmmmmmmmmmmmmdonuts/godot_4_autocomplete_issue
if (!is_function) {
				
				if (ProjectSettings::get_singleton()->has_autoload(p_symbol)) {
					const ProjectSettings::AutoloadInfo &autoload = ProjectSettings::get_singleton()->get_autoload(p_symbol);
					if (autoload.is_singleton) {
						String scr_path = autoload.path;
						if (!scr_path.ends_with(".gd")) {
							
							
							scr_path = scr_path.get_basename() + ".gd";
						}
						if (FileAccess::exists(scr_path)) {
							r_result.type = ScriptLanguage::LOOKUP_RESULT_SCRIPT_LOCATION;
							r_result.location = 0;
							r_result.script = ResourceLoader::load(scr_path);
							return OK;
						}
					}
				}
				
				HashMap<StringName, int> classes = GDScriptLanguage::get_singleton()->get_global_map();
				if (classes.has(p_symbol)) {
					Variant value = GDScriptLanguage::get_singleton()->get_global_array()[classes[p_symbol]];
					if (value.get_type() == Variant::OBJECT) {
						Object *obj = value;
						if (obj) {
							if (Object::cast_to<GDScriptNativeClass>(obj)) {
								r_result.type = ScriptLanguage::LOOKUP_RESULT_CLASS;
								r_result.class_name = Object::cast_to<GDScriptNativeClass>(obj)->get_name();
							} else {