parse error on annotation with empty arguments list

[Scony]

Godot version

v4.0.dev.custom_build.3bebbcacd

System information

manjaro linux

Issue description

This script raises ERR_PARSE_ERROR:

@onready() var x

Not sure if this is a bug or expected behavior but as this syntax is more flexible I assume this is a bug.
@vnen should clarify before this goes any further though.

Details:

$ cat tests/potential-godot-bugs/annotation-w-empty-body.gd 
@onready() var x
$ godot4 --headless --check-only -s tests/potential-godot-bugs/annotation-w-empty-body.gd
Godot Engine v4.0.dev.custom_build.3bebbcacd - https://godotengine.org
 
ERROR: Parse Error: Unexpected ")" in class body.
   at: GDScript::reload (res://tests/potential-godot-bugs/annotation-w-empty-body.gd:1)
ERROR: Method/function failed. Returning: ERR_PARSE_ERROR
   at: reload (modules/gdscript/gdscript.cpp:839)

Steps to reproduce

Execute the above

Minimal reproduction project

No response