tests/test-check-commit.t

ui: add new config option for help text width

Before this patch, when printing help text using `hg help`, or `hg log -h`,
the output will wrap at 78 chars even if the user has a bigger terminal width
and there is no config option to change it, making the experience different
from the commonly used `man` tool.

This patch introduces a new config option `ui.textwidth`, which replaces the
hardcoded number. It's set to 78 by default to maintain compatibility. When
set to 0, `hg help` will behave more like `man`.

#require test-repo

Enable obsolescence to avoid the warning issue when obsmarker are found

  $ cat >> $HGRCPATH << EOF
  > [experimental]
  > evolution=createmarkers
  > EOF

Go back in the hg repo

  $ cd $TESTDIR/..

  $ for node in `hg log --rev 'not public() and ::.' --template '{node|short}\n'`; do
  >    hg export $node | contrib/check-commit > ${TESTTMP}/check-commit.out
  >    if [ $? -ne 0 ]; then
  >        echo "Revision $node does not comply with rules"
  >        echo '------------------------------------------------------'
  >        cat ${TESTTMP}/check-commit.out
  >        echo
  >   fi
  > done