rs port: update all docs for using the new `Handle` API.

[fahdfady]

📚 Documentation

we exposed a new API Handle via this issue #589 now, the function signatures and usages are changed. we need to update the documentation, this for example: https://github.com/metacall/core/blob/bc073fc4d82ff62edd335eb75d5695bbcf9547c8/source/ports/rs_port/src/load.rs#L99-L108