Manual fixups for new hyperlinks

Manual fixups for new hyperlinks

It turns out that many manual edits were required:
- Heading underlines were too short because :any:`` is longer than ````
- Some statement names clashed with manually defined _link_anchors
  (notify, trust-anchors etc.)
- Zone types are defined like "type primary" in the internal grammar and
  that caused mayhem in the replacement script as it took "type" and
  individual types ("primary", "secondary") as separate statements.
  For that reason :any:`primary` had to be manually replaced with
  :any:`primary <type primary>` where appropriate.
- Sometimes option name is also the same as a value name (e.g. "notify")
  and then it did not make sense to do the replacement.