🔧 Fix filter to action for admin head in setup

[frugan-dev]

I understand that admin_head only exists as an action, not as a filter, or am I wrong?

[dsturm]

@frugan-dev Since add_action is merely a wrapper for add_filter, this is not a critical issue but rather a minor improvement.

[frugan-dev]

@dsturm Ok thy, I didn't know about this wrapper..

[QWp6t]

I agree with this change since it clarifies intent as add_action() and add_filter() are semantically distinct. 🙂

I also agree this isn't a bugfix.