DWiki now remembers the name and URL for links that you write with
_![[...|...]]_ and thereafter allows you to omit one side of the _|_,
at which point it will fill in the remembered values. This means that
if you want to link to [[Google|http://www.google.com]] a lot in your
document, you only have to write (eg) the URL once, and can thereafter
refer to [[Google|]] much more compactly.

This does collide a little bit with using _![[...|]]_ to write totally
unstyled text: it only comes out unstyled if it's not already been
used as the name of a link.

For now I will live with that.