Missing information about @moreinfo in the list of changes section

[tomschr]

The moreinfo attribute has been removed in DocBook 5 and upwards. According to Bob, it's "replaced by the generalized linking with XLink with an arcrole attribute."

At the moment, this isn't mentioned in the TDG:
http://www.docbook.org/tdg5/en/html/ch01.html#ch-gsxml.4
http://www.docbook.org/tdg51/en/html/ch00-online.html#changes-in-51

Original thread on the docbook mailinglist:
https://lists.oasis-open.org/archives/docbook/201606/msg00000.html