adds more details to random.md documentation

[wonk1132]

Adds more detailed documentation for the Random type, including a unit test example.

[djspiewak]

Looks like the build failures are legitimate

[wonk1132]

sorry, I don't get what I need to do to fix this issue. Can someone point me the right direction?

[armanbilge]

Looks like import errors. Use ._ instead of .*. Also cats.implicits is legacy, use cats.syntax.all.

Do you know how to run it locally? docs/mdoc in sbt console. Then you can see and fix the errors before you push.

Thanks for your work!

[sshark]

I feel we should retain the example of using Random in the dieRoll generic function in https://typelevel.org/cats-effect/docs/std/random#using-random

def dieRoll[F[_]: Functor: Random]: F[Int] =
  Random[F].betweenInt(0, 6).map(_ + 1) 

I would like to expand this example into a working copy-and-paste example. This example at current state does not show how dieRoll is used together with an implicit Random instance. Thank you