Fix references to un-exported definitions in other specs.

[cfredric]

The spec refers to a handful of terms from other specs whose definitions are not exported, or are ambiguous. Those other specs should be updated to export those items properly and unambiguously. Once that is done, the link-defaults and anchors sections of this spec should be removed.

[annevk]

@cfredric looks like you fixed this?

[cfredric]

I haven't worked on this. If the existing lines under link-defaults and anchors are no longer necessary, that must have been due to someone else's work.