### Godot version

4.0beta12

### System information

all

### Issue description

In `extension_api.json` we have some function that uses parameter typed after a global enum and display it as a bitfield:
```js
{
	"name": "set_button_mask",
	"is_const": false,
	"is_vararg": false,
	"is_static": false,
	"is_virtual": false,
	"hash": 3950145251,
	"arguments": [
		{
			"name": "mask",
			"type": "bitfield::MouseButtonMask" // bitfield prefix here !
		}
	]
},
```

However the global enum's own definition doesn't mention it is a bitfield:
```js
{
	"name": "MouseButtonMask",
	// No "bitfield" field here !
	"values": [
		{
			"name": "MOUSE_BUTTON_MASK_LEFT",
			"value": 1
		},
		{
			"name": "MOUSE_BUTTON_MASK_RIGHT",
			"value": 2
		},
		{
			"name": "MOUSE_BUTTON_MASK_MIDDLE",
			"value": 4
		},
		{
			"name": "MOUSE_BUTTON_MASK_MB_XBUTTON1",
			"value": 128
		},
		{
			"name": "MOUSE_BUTTON_MASK_MB_XBUTTON2",
			"value": 256
		}
	]
},
```

On the other hand, the non-global enums (i.e. the ones defined as part of a class) have this `is_bitfield` field.
So I guess we should add it to global enum too.

### Steps to reproduce

n/a

### Minimal reproduction project

n/a
Dictionary d;
			d["name"] = s.name;
			if (s.class_name != StringName()) {
				d["type"] = String(s.class_name);
			} else {
				d["type"] = String(s.ptr->get_class());
			}
			singletons.push_back(d);
		}
		if (singletons.size()) {
			api_dump["singletons"] = singletons;
		}
	}
	{
		Array native_structures;
		List<StringName> native_structs;
		ClassDB::get_native_struct_list(&native_structs);
		native_structs.sort_custom<StringName::AlphCompare>();
		for (const StringName &E : native_structs) {
			String code = ClassDB::get_native_struct_code(E);
			Dictionary d;
			d["name"] = String(E);
			d["format"] = code;
			native_structures.push_back(d);
		}
		api_dump["native_structures"] = native_structures;
	}
	return api_dump;
}
void GDExtensionAPIDump::generate_extension_json_file(const String &p_path) {