obslog: colorize the description diff shown in obslog -p
This patch colorizes the description diff shown in `hg obslog -p`. The labels
for the header are different from that of the patch as the main header which
says `diff -r <somehash> -r <somehash> <filename>`. Next patch will hack to add
that.
#require test-repo pyflakes
Copied from Mercurial core (60ee2593a270)
$ cd "`dirname "$TESTDIR"`"
run pyflakes on all tracked files ending in .py or without a file ending
(skipping binary file random-seed)
$ hg locate 'set:(**.py or grep("^#!.*python")) - removed()' 2>/dev/null \
> | xargs pyflakes 2>/dev/null