It was trying to link unlinked text, but got in a bit of a mess when
links are nested in other markup. Also reads the 'quickbook-escape'
content, now it's just checking for the presence of links that should be
fine.
When adding links, don't add them around other links. If there's
anything outside of existing links, they'll still get linked. Although,
maybe it would be better to only add link tags when the title doesn't
contain any links. This might be over-complicated and confusing.
