Catch up to highlight 3.51 API change.

[ikiwiki] / doc / bugs / inline_postform_empty_title.mdwn

When using inline with postform=yes, the user can click on the edit button
without providing a title, and are allowed to save the page. This results
in a file with a name like ".mdwn", which ikiwiki won't render.
--[[Joey]]

> [[done]]; made it error out in this case.