extdiff: prevent exception on double-translation
The docstring is translated twice: once when used as a format string,
and once on display. The second translation fails when the first
translation introduces non-ASCII characters in the string.
The problem is that the gettext module calls unicode(message) on the
string, i.e., it decodes it to a Unicode string using the ASCII
encoding (the default encoding). By translating it into a Unicode
string here, the unicode() call becomes a noop.
% try to commit on top of a patch
abort: cannot commit over an applied mq patch
% qpop/qrefresh on the wrong revision
abort: popping would remove a revision not managed by this patch queue
using patch queue:
abort: popping would remove a revision not managed by this patch queue
abort: working directory revision is not qtip
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
% qpop
abort: popping would remove a revision not managed by this patch queue
% qrefresh
abort: cannot refresh a revision with children
% tip:
3 append quux