[WM] [Q] define tag _and_ empty_tag

[Justin Mason]

Chris said:

> does anybody happen to know if it is possible to define a normal (open/close)
> _and_ and empty tag with the same name, similar to the built in tag <wmmeta>?

ack!

originally tags did both, as you suggest.  I took this out for efficiency,
as it meant two searches were run internally -- one for standalone and one
for open/closed use.

I can re-add it if you like -- but are you sure it's needed?  IMO I went
overboard with the wmmeta tag's flexibility, and nowadays we pay for
it in performance.

--j.