[Mutt] #2921: using ~(pattern) fails when not sort=thread without notice

[Mutt <fleas@xxxxxxxx>]

#2921: using ~(pattern) fails when not sort=thread without notice

 The {{{~(pattern)}}} pattern fails when {{{sort!=thread}}}:
 rather than giving the desired list, it just beeps in error for not
 matching anything (muttdebug).
 Unfortunately there is no pointer in the status-line giving a clue why it
 fails.
 Also it isn't documented.

 Ideally {{{~()}}} could work in other sort-modes, too, but until this
 works,
 a note in the docs and an error message in the status line would help
 analyzing mismatches.

-- 
Ticket URL: <http://dev.mutt.org/trac/ticket/2921>