gendoc: do not strip 'hg ' from synopsis
This was an old left-over from when the synopsis line was used as a
header. We now have the command name by itself as the header and the
synopsis as a literal block immediately after..
$ hg init repo
$ cd repo
$ touch foo
$ hg ci -Am 'add foo'
adding foo
$ hg up -C null
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
this should be stored as a delta against rev 0
$ echo foo bar baz > foo
$ hg ci -Am 'add foo again'
adding foo
created new head
$ hg debugindex .hg/store/data/foo.i
rev offset length base linkrev nodeid p1 p2
0 0 0 0 0 b80de5d13875 000000000000 000000000000
1 0 24 0 1 0376abec49b8 000000000000 000000000000