Don't xref <span>s with attributes, or switch to <a>

[zcorpan]

#33 (comment)

There's a disconnect between what gets xreffed and what is caught as an error. This is not a huge problem I suppose but still, whenever <span class="something"> or so is used and it is intended not to be an xref, it could be picked up as an xref and might not be noticed.

[tabatkins]

Switching to <a> without href as the market for an autolink was a great move on my part for Bikeshed, I'd recommend doing it.