7176: Attribute completion r=matklad a=FlowerBOII
Solve #7167.
I removed the optional args for the attributes ```deprecated```, ```must_use``` and ```should_panic```.
I also updated their respective tests.
Please let me know if I missed something.
Co-authored-by: FlowerBOII <42295129+FlowerBOII@users.noreply.github.com>