graphlog: document what "_" and "*" mean
Documenting "*" should've been a part of 9b3f95d9783d, but I somehow didn't
notice that the symbols are explained in the command's help text.
#require test-repo jshint hg10
$ . "$TESTDIR/helpers-testrepo.sh"
run jshint on all tracked files ending in .js except vendored dependencies
$ cd "`dirname "$TESTDIR"`"
$ testrepohg locate 'set:**.js' \
> 2>/dev/null \
> | xargs jshint