Introduced `lol.Tracer` for function entry/exit logging across various packages. This improves traceability and debugging of function executions while preserving existing behavior. Removed unused files `doc.go` and `nothing.go` to clean up the repository.
the improvements:
- eliminate double definition of marshal/unmarshal interface
- proper single a tag codec using teh codec.JSON interface
- kind constructor using constraints.Integer to make invocations from random integer types easier
- eliminate separate string constructor for arb elements using generics
