topics: fix auto-publish=abort with servers publishing bare branches Before this change, servers that automatically publish bare branches were detected as "non publishing" and the check for automatic publishing on push assumed nothing was to be published. Now we signal the server-side config to clients via a new capability so that they can adjust their behavior.

#require test-repo pyflakes

Copied from Mercurial core (60ee2593a270)

  $ cd "`dirname "$TESTDIR"`"

run pyflakes on all tracked files ending in .py or without a file ending
(skipping binary file random-seed)

  $ hg locate -I 'set:(**.py or grep("^#!.*python")) - removed()' 2>/dev/null \
  > | xargs pyflakes 2>/dev/null