Remove unneeded setter return values

[appgurueu]

Fixes #12177. I consider return values unneeded when:

• It's a true boolean indicating success
• It's undocumented
• The only case in which a falsy return value (can be nothing) is returned is an invalid player object, which should be checked against using is_player() instead

[appgurueu]

I've found no push* within the set_look_* funcs (or any of the called funcs) and testing shows that these functions return nothing on success. I therefore have to assume that the 1 is incorrectly returned.

[rubenwardy]

No mods or games use the return value of set_local_animation. (Character Anim returns it but then ignores that)

The other functions return the last argument, assuming it isn't popped in the method

[rubenwardy]

I found invalid 0 uses of the return value when looking through the search results for player:set_

This doesn't match all uses, but is enough for me to be sufficiently confident that the impact will be minimal

[appgurueu]

Character Anim returns it but then ignores that

Yeah, that's a tail call. Probably not really needed though.

[rubenwardy]

LGTM now