Add Documentation for Lizard Extensions

[Ollec]

Why

The lizard_ext folder contains 19+ powerful extensions (metrics, analyzers, output formatters) but lacked documentation. Users couldn't easily discover what extensions exist, how to use them, or how to integrate them into CI/CD pipelines.

What

• New: lizard_ext/README.md - Complete documentation for all extensions with:
  • Command-line flags and usage examples
  • Real output samples from running lizard on itself
  • CI/CD integration examples (Jenkins, GitHub Actions, GitLab)
  • Use cases and best practices
• Updated: README.rst - Added link to extensions documentation
• Added: Image placeholders for HTML report and word cloud screenshots

Categories Covered

• Metrics: Nesting depth, nested structures, fan-in/fan-out, statement counts, etc.
• Analysis: Duplicate detection, comment extraction, parameter list analysis
• Modifiers: Ignore assertions, modified CCN, preprocessor handling
• Formatters: CSV, HTML (interactive), XML, Checkstyle