Aliasing dbz → dragon_ball_z
Link to alias

Reason:

I was looking at recent changes, saw someone removed a "dbz" tag because it was already tagged with "Dragon_ball_z".
The tag "dbz" is not in use and it is pretty common for dragon ball z to be shortened to dbz(Not on e621, but in general by fans or people talking about dbz in general).

Definitely seen this one a lot in the past (and google seems to agree). Approved