docs: this PR provides comprehensive documentation for all macros covered in `binding.md`

[HMarcien]

Key changes include:

• New Structure: Reorganized the file into logical sections: Top-Level Definitions, Local Bindings, Procedure Abstractions, and Derived/Auxiliary Forms, with improved introductions.
• Complete Documentation: Added detailed documentation for all binding forms, including:
  • Top-Level: def, def*, defvalues, extern, defsyntax, defrules, defrule, defalias.
  • Local Bindings: let, let*, letrec, letrec*.
  • Procedure Abstractions: lambda, case-lambda.
  • Derived Forms: cut, let/cc, rec, alet, alet*.