phabricator: clarify the multiple heads/roots error message for phabsend
As pointed out in followup feedback for
c1c922391314, it's confusing to say
there are multiple items and then only list one.
Differential Revision: https://phab.mercurial-scm.org/D8761
max_width = 79
wrap_comments = true
error_on_line_overflow = true