tests/test-issue4074.t

help: eliminate duplicate text for revset string patterns

There's no reason to duplicate this so many times, and it's likely an instance
will be missed if support for a new pattern is added and documented.  The
stringmatcher is mostly used by revsets, though it is also used for the 'tag'
related templates, and namespace filtering in the journal extension.  So maybe
there's a better place to document it.  `hg help patterns` seems inappropriate,
because that is all file pattern matching.

While here, indicate how to perform case insensitive regex searches.

#require no-pure

A script to generate nasty diff worst-case scenarios:

  $ cat > s.py <<EOF
  > import random
  > for x in xrange(100000):
  >     print
  >     if random.randint(0, 100) >= 50:
  >         x += 1
  >     print hex(x)
  > EOF

  $ hg init a
  $ cd a

Check in a big file:

  $ python ../s.py > a
  $ hg ci -qAm0

Modify it:

  $ python ../s.py > a

Time a check-in, should never take more than 10 seconds user time:

  $ hg ci --time -m1
  time: real .* secs .user [0-9][.].* sys .* (re)