This is a follow up to #602, documenting the new
behavior.
</entry>
<entry>add, remove, or toggle notmuch tags; [+]<tag> to
add, -<tag> to remove, !<tag> to togglelabels and
- then hide message by applying the "quasi-deleted" state.
+ then hide or unhide the message by changing the "quasi-deleted"
+ to match if it would be shown when requerying.
Normal redisplay rules apply here, so the user must call
<sync-mailbox> for the changes to be displayed. Note:
Tab completion of tag names is available.</entry>