`5.1.1.0` release checklist

[Anut-py]

• Documentation
  • [x] Update README.md
  • [x] Update DOCUMENTATION.md
  • [x] Update CHANGELOG.md
  • [x] Update CONTRIBUTING.md
  • [x] Check Haddock documentation for completeness
• Submodules
  • [x] Update raylib
  • [x] Update raygui
  • New submodules
    • [x] Add to cabal config
    • [x] Add to nix config
    • [x] Add to devtools.js
    • [x] Create example
  • New structures
    • [x] Add to Raylib.Util.Lenses
• General
  • [x] Increment cabal version
  • [x] Run devtools.js -u
  • New examples
    • [x] Add to cabal config
    • [x] Add to run-all-examples.sh
  • Prerelease
    • [x] Check if GitHub actions is successful
    • [x] Run devtools.js -p
• [x] Create release tag