view mercurial/__init__.py @ 17119:2e13c1bd34dc

graphlog: display obsolete changeset as "x"

Changeset detected as obsolete will be displayed as "x" instead of 'o':

    o new rewritten changeset
    |
    | x old obsolete changeset
    |/
    |
    o base

This will be useful even when some obsolete changeset will be "hidden" because
not all obsolete changeset can be hidden. If an obsolete changeset have
non-obsolete descendant we can't simply hide it. And having a clear visual hint
that the changeset is obsolete is useful.

The main reason to make this minor change right now is to:

1) introduce an officiel user of the `ctx.obsolete()` method that will detect
   breakage earlier than third party code (mutable, hgview)

2) Do not display any vocabulary related to obsolete. Such vocabulary will
   require discussion.