Add -h short option for help

[techtonik]

Fixes https://bugs.launchpad.net/snapcraft/+bug/1807423

https://click.palletsprojects.com/en/7.x/documentation/#help-parameter-customization

• Have you followed the guidelines for contributing?
• Have you signed the CLA?
• Have you successfully run ./runtests.sh static?
• Have you successfully run ./runtests.sh tests/unit?

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[sergiusens]

Hi there, have you indeed signed the CLA, the tests says no but you marked the checkbox

[cjp256]

Refreshed and CLA check passed.

[codecov-io]

Codecov Report

Merging #2527 into master will decrease coverage by 0.04%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #2527      +/-   ##
==========================================
- Coverage   89.13%   89.08%   -0.05%     
==========================================
  Files         208      207       -1     
  Lines       14201    14094     -107     
  Branches     2152     2131      -21     
==========================================
- Hits        12658    12556     -102     
+ Misses       1091     1086       -5     
  Partials      452      452

Impacted Files	Coverage Δ
snapcraft/cli/_runner.py	91.83% <100%> (ø)	⬆️
snapcraft/plugins/ant.py	86.61% <0%> (-2.28%)	⬇️
snapcraft/internal/pluginhandler/_plugin_loader.py	83.33% <0%> (-1.97%)	⬇️
snapcraft/plugins/rust.py	94.44% <0%> (-0.89%)	⬇️
snapcraft/cli/ci.py	86.66% <0%> (-0.84%)	⬇️
snapcraft/internal/elf.py	80.71% <0%> (-0.36%)	⬇️
snapcraft/internal/sources/_script.py	100% <0%> (ø)	⬆️
snapcraft/plugins/conda.py
snapcraft/cli/lifecycle.py	86.95% <0%> (+0.09%)	⬆️
snapcraft/cli/_options.py	89.47% <0%> (+7.25%)	⬆️
... and 1 more

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[techtonik]

Rebased and squashed black fixes.

[techtonik]

spread test times out. No idea what does it do.

[techtonik]

@sergiusens thanks!