Diff and check command line formatting

[kieran-ryan]

🤔 What's changed?

• Exit code 1 if files reformatted or would be reformatted
• --check option to check whether reformatting would occur without writing changes
• --diff option to check whether reformatting would occur without writing changes; and output diff
• Support formatting against directories
• Counts for failures, unchanged and formatted files

> npx @cucumber/gherkin-utils format features
❌ 7 files failed to format
🥒 14 files left unchanged
🥒 25 files reformatted

Debt

• Prevent writing back to file if no changes to be made
• Updated issues URL in parser error message from common repo to gherkin parser
• Migrated from deprecated commander-js API to specify argument descriptions in .description rather .argument
• Updated README from outdated --move API to --to-syntax

⚡️ What's your motivation?

• Enables increased proliferation of Gherkin Utils across repositories containing feature files - for validating formatting in continous integration pipelines
• Simplifies usage to run Gherkin Utils against directories containing feature files
• Enables checking would formatting occur without writing changes
• Counts provides much greater clarity on changes

Debt

• Eliminate redundant write operations
• Ensure parse error messages raised to correct repository
• Ensure commander-js using latest APIs
• Align docs with latest API

🏷️ What kind of change is this?

• ⚡ New feature (non-breaking change which adds new behaviour)

♻️ Anything particular you want feedback on?

• Whether should default formatter to run against a features directory (e.g. npx @cucumber/gherkin-utils format) to simplify common usage
• Whether can remove --from-syntax command line option. Not sure is required as syntax (gherkin or markdown) can be determined

📋 Checklist:

• I agree to respect and uphold the Cucumber Community Code of Conduct
• I've changed the behaviour of the code
  • I have added/updated tests to cover my changes.
• My change requires a change to the documentation.
  • I have updated the documentation accordingly.
• Users should know about my change
  • I have added an entry to the "Unreleased" section of the CHANGELOG, linking to this pull request.

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