tests/test-sparse-fsmonitor.t

rust: update `clap` to the latest 4.x version

This brings in more up-to-date dependencies, some bug fixes (none of which are
relevant yet), and slightly improved compile times.

This test doesn't yet work due to the way fsmonitor is integrated with test runner

  $ exit 80

test sparse interaction with other extensions

  $ hg init myrepo
  $ cd myrepo
  $ cat > .hg/hgrc <<EOF
  > [extensions]
  > sparse=
  > strip=
  > EOF

Test fsmonitor integration (if available)
TODO: make fully isolated integration test a'la https://github.com/facebook/watchman/blob/master/tests/integration/WatchmanInstance.py
(this one is using the systemwide watchman instance)

  $ touch .watchmanconfig
  $ echo "ignoredir1/" >> .hgignore
  $ hg commit -Am ignoredir1
  adding .hgignore
  $ echo "ignoredir2/" >> .hgignore
  $ hg commit -m ignoredir2

  $ hg sparse --reset
  $ hg sparse -I ignoredir1 -I ignoredir2 -I dir1

  $ mkdir ignoredir1 ignoredir2 dir1
  $ touch ignoredir1/file ignoredir2/file dir1/file

Run status twice to compensate for a condition in fsmonitor where it will check
ignored files the second time it runs, regardless of previous state (ask @sid0)
  $ hg status --config extensions.fsmonitor=
  ? dir1/file
  $ hg status --config extensions.fsmonitor=
  ? dir1/file

Test that fsmonitor ignore hash check updates when .hgignore changes

  $ hg up -q ".^"
  $ hg status --config extensions.fsmonitor=
  ? dir1/file
  ? ignoredir2/file