Alias eyes_half_closed -> half-closed_eyes

BUR #8282 has been approved by @nonamethanks.

create alias eyes_half_closed -> half-closed_eyes

Makes it easier to find. eyes closed and eyes covered are already aliased.

This will shift all the other eyes_ tags further down the autocomplete, but we already have several eyes_ -> _eyes aliases, so I guess it doesn't matter much.

The bulk update request #8282 (forum #202461) has been approved by @nonamethanks.