bug#47566: 28.0.50; diff-hl should use `repeat-mode' ... and not `smartrep'

[Juri Linkov]

>> Consider adding a repeat-mode-echo option which follows what Smartrep
>> does: instead of adding to the echo area, it just highlights the
>> changed state in the mode line (basically a long mode lighter saying
>> "========SMARTREP=======") and also colors the mode-line green.
>>
>> IME that works well as an indicator that we're in a "special" state.
>>
>> Though perhaps we could use a smaller text (like "[REPEAT]") and only
>> color the text inside the brackets, rather than the whole
>> mode-line. Could use some experimentation.
>
> An entry in mode-line-modes, à la compilation-in-progress, would be
> lovely IMO.

compilation-in-progress is a good example of an unobtrusive indicator
in the mode line.  Now added to repeat-mode.

PS: like your message-subject-re-regexp turned the subject into
"Re: peat lambda" on emacs-devel, it removed the bug number
from the subject here :)