"Must be keyword" in Frame class docstrings?

[ayshih]

This may be a silly question, but why do many Frame class docstrings (still) say "must be keyword" for parameters that don't actually have to be keywords? It looks like an old PR noted this problem but deferred fixing it (#6219 (comment)), and a later PR claims to fix them but doesn't appear to have done anything substantial in this area (#6260 (comment)). There may be other relevant discussion that I'm unaware of.

For context, we're cleaning up docstrings on SunPy, and I'd like to know whether we should have those odd "must be keyword" clauses.

[pllim]

@adrn ?