I can't make more than one alias request at a time, and I don't know how to make bulk update requests because I've never done it before, so I'll just let someone else do it.

Here's the bulk update request listed below:
create alias head_lights -> headlight
create alias head_light -> headlight
create alias headlights -> headlight

Reason: Plural to singular. The word without the space is the proper version.

Not meant to be confused with headlamp according to the wiki page: A head-mounted personal equipment.

The bulk update request #11359 is active.

create alias head_lights (2) -> headlight (467)
create alias head_light (5) -> headlight (467)
create alias headlights (3) -> headlight (467)

Reason: As requested in OP.

Templates for the desired lines can be found if you click on the little "Help" under the Script box. Plug in a Title, a Reason, and assuming you want to attach it to a particular thread, put the thread's ID (found on the end of the url, eg. 57518 for this thread) under Forum topic. Hit Submit, and Bob's your uncle.

EDIT: The bulk update request #11359 (forum #454085) has been approved by @spe.

The bulk update request #11359 (forum #454085) has been approved by @spe.