Misleading documentation: the native recorder seems to be using rb_add_event_hook2, *not* the "TracePoint API"

[nickysn]

The current README states:

Current approach: TracePoint API

Currently we're using the [TracePoint API](https://rubyapi.org/3.4/o/tracepoint). This is very flexible and can function with probably multiple Ruby versions out of the box. However, this is limited:

    it's not optimal
    it can't track more detailed info/state, needed for some CodeTracer features(or for more optimal replays).

For other languages, we've used a more deeply integrated approach: patching the interpreter or VM itself (e.g. Noir).

Possible Alternative Approaches

Create a C extension for the VM, based on the rb_add_event_hook2
This would be a straight-forward port of the current code, but developed as a native extension (e.g. in C/C++ or Rust). The expected speedup will be significant.

Examining the source code of the native recorder, written in Rust lead to the discovery that we're already using the undocumented rb_add_event_hook2() API function, mentioned as "Possible Alternative Approaches", with the undocumented RUBY_EVENT_HOOK_FLAG_RAW_ARG parameter. I'm not sure about the "Pure" Ruby recorder, though. This still needs to be checked, but the documentation needs to be updated.