All tagging operations ('+', '-', '`*`') now accept multiple tags with
'+' or '-' prefix, like '`*`' operation in notmuch-search view before.
- `*` operation (`notmuch-show-tag-all`) is now available in
+ '`*`' operation (`notmuch-show-tag-all`) is now available in
notmuch-show view.
`notmuch-show-{add,remove}-tag` functions no longer accept tag