When I create a backtag to a Thing with a Space in its name, the tag is slightly wrong

(Bug, Closed -> Fixed, Priority: Critical, Test Status: No automated tests yet , Reported By Justin du Coeur, )
Tag Sets, Editor
Summary: Noticed while working on the Period Games Space. When I create an External Page from, say, "Byzantine Chess", the backlink tag is to "Byzantine-Chess". This works as a link, but is not noticed in _tagRefs.
I'll enter a separate bug for _tagRefs, but this one is wrong in and of itself.