Adding `toRightIn` and `toOptionIn`

[typelevel]

Adding `toRightIn` and `toOptionIn`

[danicheg]

I think these methods would be quite helpful. So green light for opening PR from me 🙂

[satorg]

Btw, I think that for toRightIn and toLeftIn it would be also helpful to have their F counterparts:

def toLeftInF[R](right: => F[R])(implicit F: Monad[F]): F[Either[A, R]] = ???
def toRightInF[L](left: => F[L])(implicit F: Monad[F]): F[Either[L, A]] = ???

It would similar to the corresponding methods toRightF and toLeftF from OptionT.

[benhutchison]

Green light from me, with or without @satorg proposed F-variant

[satorg]

Perhaps, it would be better to call them toOptionT, toRightT, etc. IMO it would be more clear from the naming what exactly these methods do, wdyt?

UPD. Oops. Disregard please. Sorry, I didn't get that these methods are not for monad transformers like OptionT.