[m-rev.] diff: don't repeat an error explanation

[Zoltan Somogyi]

This should not need review.

Zoltan.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Log.ii
Type: application/octet-stream
Size: 446 bytes
Desc: not available
URL: <http://lists.mercurylang.org/archives/reviews/attachments/20231019/4056e098/attachment.obj>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: DIFF.ii
Type: application/octet-stream
Size: 3185 bytes
Desc: not available
URL: <http://lists.mercurylang.org/archives/reviews/attachments/20231019/4056e098/attachment-0001.obj>