I just accidentally checked the 'community wiki' box when posting an answer, while I tried to copy it for a google search about what that even meant.
Is there a way to undo that?
I went in and hit the metaphorical Ctrl-Z (or CMD-Z for the Mac OS crowd) on that Community Wiki post; it's now been de-community wikified.
If this happens, you can always flag your post for moderator attention and use the "other" box to describe the issue, and one of us can make the change. Also, posting here, as you did, is fine as well. Hope this helps!