Fix IOFrame usage in IOBracket

[nomisRev]

IOFrame was not correctly called unless manually wrapped in IO.Bind. It did not run using flatMap like Cats-effect's IO because IO.RaiseError is overridden to short-circuit flatMap like this override fun <B> flatMap(f: (Nothing) -> IOOf<B>): IO<B> = this

To leave the overridden function as explicit as it currently is I opted to elaborate in the IOFrame docs how to properly use it. Also, I added a test for this and changed the usage in IOBracket.

Do we want to keep it like this or shall we override IO.RaiseError#flatMap as follows to prevent similar bugs by miss-use in the future?

override fun <B> flatMap(f: (Nothing) -> IOOf<B>): IO<B> =
      if (f is IOFrame) Bind(this, f as (Nothing) -> IO<B>) else this