tests/test-debugindexdot.out

hg: say 'hg update' instead of 'hg up' in merge status message

Includes the change to the message itself, along with several test
output files that also had to change.

created new head
digraph G {
	-1 -> 0
	0 -> 1
	0 -> 2
	2 -> 3
	1 -> 3
}