Sense renumbering detection

[stuartpb]

Tooling should be able to detect if a sense has been moved in a definition from the previous commit to the next, and other words pointed to that sense, meaning that that pointer needs to be updated

[stuartpb]

Maybe there should be some kind of identifier, like the use is copied, or at least recapped in the form of a search string that should only apply to one sense (and always apply for only that sense through rewrites).