tests/test-check-help.t

logexchange: convert paths to unix when detecting the active path

This fixes the problem in the tests[1] where Windows was showing the whole path
as the remotename for local repositories.

Somebody with a better understanding of this extension should probably take a
deeper look.  There may be other cases that need to be converted- specifically
the `elif not instance` and the missing `else` cases in activepath().  I also
noticed when adding debug prints that the absolute path is stored in the file,
probably not normalized.  (It's wrapped up in $TESTTMP.)

[1] https://buildbot.mercurial-scm.org/builders/Win7%20x86_64%20hg%20tests/builds/1042/steps/run-tests.py%20%28python%202.7.13%29/logs/stdio

#require test-repo

  $ . "$TESTDIR/helpers-testrepo.sh"

  $ cat <<'EOF' > scanhelptopics.py
  > from __future__ import absolute_import, print_function
  > import re
  > import sys
  > if sys.platform == "win32":
  >     import msvcrt
  >     import os
  >     msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY)
  > topics = set()
  > topicre = re.compile(br':hg:`help ([a-z0-9\-.]+)`')
  > for fname in sys.argv:
  >     with open(fname, 'rb') as f:
  >         topics.update(m.group(1) for m in topicre.finditer(f.read()))
  > for s in sorted(topics):
  >     print(s)
  > EOF

  $ cd "$TESTDIR"/..

Check if ":hg:`help TOPIC`" is valid:
(use "xargs -n1 -t" to see which help commands are executed)

  $ testrepohg files 'glob:{hgdemandimport,hgext,mercurial}/**/*.py' \
  > | sed 's|\\|/|g' \
  > | xargs "$PYTHON" "$TESTTMP/scanhelptopics.py" \
  > | xargs -n1 hg help --config extensions.phabricator= > /dev/null