Correctly specify the decorator name that should be used to give an
instrument method appropriate priority when it's being invoked via
signal dispatch.
Previously, the table was listing the priority enum names in the column
that was labeled "decorator". Now both are shown and the distinction has
been made clearer.
Add a decorator to indicate that a callback runs entirely host-side and
does not rely on a connection to the target. This means it will be
invoked even if the target was detected to be unresponsive.
