Allows users to take advantage of the linking mechanism in their editing
tools outside of the 'zk.new' context. For example, I made a
"ZkInsertLink" command that inserts a link at the current cursor location
after searching for the desired note. This improves on the current
behavior which only autocompletes based on note name, which users may or
may not remember.

Some extra bool values were previously returned in linkNote and the
zk.link LSP command. These values were vestigial placeholders from
the initial refactor, in case extra information was useful. It turns out
this was not the case.

Also updates CHANGELOG to reflect the zk.link contribution