### 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
d[key.value] = value.value;
						} else {
							full = false;
							break;
						}
					} else {
						full = false;
						break;
					}
				}
				if (full) {
					r_type.value = d;
					r_type.type.is_constant = true;
				}
				r_type.type.type_source = GDScriptParser::DataType::ANNOTATED_EXPLICIT;
				r_type.type.kind = GDScriptParser::DataType::BUILTIN;
				r_type.type.builtin_type = Variant::DICTIONARY;
				found = true;
			} break;
			case GDScriptParser::Node::ARRAY: {
				
				const GDScriptParser::ArrayNode *an = static_cast<const GDScriptParser::ArrayNode *>(p_expression);
				Array a;
				bool full = true;
				a.resize(an->elements.size());
				for (int i = 0; i < an->elements.size(); i++) {
					GDScriptCompletionIdentifier value;
					if (_guess_expression_type(p_context, an->elements[i], value)) {
						if (value.type.is_constant) {
							a[i] = value.value;