small files may be their own checkin log message

sometimes I find myself taking the contents of a small file that I am checking in, e.g. with hg ci,
and inserting the contents of that file as the checkin log mesage.

I.e. sometimes the file itself explains what it is better than words can.

Typical for small scripts, on or two liners.

This makes some history messages that interleave log message and file contents ugly.

Note: often not the entire checking log.  Often I put a little bit of text explaining.