New semantics for empty link text.

[netcarver]

Currently empty link text (like blah "":url...) is not treated as a valid link. Could something more useful be done with it in the next major version release? For example; it could perhaps be made to duplicate the "$":url construct.

I tried this in bd93368ab79 (now reverted as it breaks compatibility) and it works just fine. If wanted we just need to agree what to do with that syntax and when to introduce it as a feature.

[gocom]

In my opinion "":url should generate <a href="url"></a>, if it must generate anything.