### 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
Callable::CallError ce;
				bool v1_use_value = p1.value.get_type() != Variant::NIL && p1.value.get_type() != Variant::OBJECT;
				Variant d1;
				Variant::construct(p1.type.builtin_type, d1, nullptr, 0, ce);
				Variant d2;
				Variant::construct(p2.type.builtin_type, d2, nullptr, 0, ce);
				Variant v1 = (v1_use_value) ? p1.value : d1;
				bool v2_use_value = p2.value.get_type() != Variant::NIL && p2.value.get_type() != Variant::OBJECT;
				Variant v2 = (v2_use_value) ? p2.value : d2;
				
				if ((op->variant_op == Variant::OP_DIVIDE || op->variant_op == Variant::OP_MODULE) && v2.get_type() == Variant::INT) {
					v2 = 1;
					v2_use_value = false;
				}
				if (op->variant_op == Variant::OP_DIVIDE && v2.get_type() == Variant::FLOAT) {
					v2 = 1.0;
					v2_use_value = false;
				}
				Variant res;
				bool valid;
				Variant::evaluate(op->variant_op, v1, v2, res, valid);
				if (!valid) {
					found = false;
					break;
				}
				r_type = _type_from_variant(res);
				if (!v1_use_value || !v2_use_value) {
					r_type.value = Variant();
					r_type.type.is_constant = false;
				}