dirstate-v2: add flag to `debugstate` to print docket information
This is useful information that we don't easily have access to currently,
unless you speak fluent xxd.
This replaces `debugdirstateignorepatternshash`, which I'll remove in the next
changeset.
Differential Revision: https://phab.mercurial-scm.org/D12590
cat >> $HGRCPATH <<EOF
[extensions]
narrow=
[experimental]
changegroup3 = True
EOF