Hardcode snippet output

Author: mariogalic

_overviews/collections-2.13/conversion-between-option-and-the-collections.md

@@ -18,6 +18,7 @@ for {
   a <- Set(1)
   b <- Option(41)
 } yield (a + b)
+// : Set[Int] = Set(42)
 ``` 
 
 since the operation `flatMap` on the type `Set[Int]` takes a function returning an `IterableOnce`:
@@ -37,12 +38,14 @@ so although `Option[A]` is not a full collection it can be _viewed_ as one. For
 
 ```scala mdoc
 Some(42).drop(1)
+// : Iterable[Int] = List()
 ```
 
 expands to
 
 ```scala mdoc
 Option.option2Iterable(Some(42)).drop(1)
+// : Iterable[Int] = List()
 ```
 
 because `drop` is not defined on `Option`. A downside of the above implicit conversion is that instead of getting back an `Option[A]` we are left with an `Iterable[A]`. For this reason, `Option`’s documentation carries the following note: