n-api,doc: clarify napi_finalize related APIs

All these APIs have napi_finalize parameter but they don't behave
exactly the same.

Fixes: https://github.com/nodejs/node/issues/29750

PR-URL: https://github.com/nodejs/node/pull/29797


Reviewed-By: Gabriel Schulhof <gabriel.schulhof@intel.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>