Is editing the question to replace "right to work" with "employment at will" the right thing to do?
After clarifying in comments (as done in the post) if that is the proper phrase then yes.
When in doubt it is always OK to ask here on Meta as you did, or on chat about the proper way of handling these sort of things. I understand that you may be thinking this more thoroughly as now with 2k+ rep your edits take effect immediately, so one has to be more careful with them.
About this situation I see no problem with that edit; in fact, there was a highly voted comment that pointed out that mistake. When I see comments like this it is an indication that an edit like the one you suggest would help.
The good thing is that edits can be rolled back, edited again, etc., so if by any chance the changes you made were not optimal surely someone else may come to correct that (however, one should not count on this and double check your own edits).