tests/test-check-help.t

log: remove dead code to follow descendants if ascending revisions specified

It's been disabled since 8b4b9ee6001a "log: make -fr show complete history
from the given revs" 2015-02-06, and we've got no bug report regarding this
exact behavior. For details what the heck "followdescendants" is, please see
the issue comment:

https://bz.mercurial-scm.org/show_bug.cgi?id=4959#c72

"'rev(%d)' % startrev" can be replaced with '.' since revs are 'reversed(:.)'.

#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 os, msvcrt
  >     msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY)
  > topics = set()
  > topicre = re.compile(r':hg:`help ([a-z0-9\-.]+)`')
  > for fname in sys.argv:
  >     with open(fname) 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 > /dev/null