topicidx: stop assigning index number to obsolete changesets
Obsolete changeset are no longer part of the stack, the old logic tried to
assigns them the index of their successors but this is flacky and error prone.
So we stop doing so.
import hghave
@hghave.check("docgraph-ext", "Extension to generate graph from repository")
def docgraph():
try:
import hgext.docgraph
hgext.docgraph.cmdtable # trigger import
except ImportError:
try:
import hgext3rd.docgraph
hgext3rd.docgraph.cmdtable # trigger import
except ImportError:
return False
return True