I have a bunch of tag pages autogenerated by the tag plugin. As part of a redesign for my wiki, I have changed the `autotag.tmpl` template, but IkiWiki refuses to rebuild existing tag pages using the updated template. I understand that existing tag pages are not rebuilt because they have been marked as "created" in `.ikiwiki/indexdb`. Is there a way to purge all tag pages from `indexdb`? --dkobozev