Evaluate snippets with mdoc

Author: mariogalic

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

@@ -13,12 +13,11 @@ permalink: /overviews/collections-2.13/:title.html
 
 Hence `Option` can be used everywhere an `IterableOnce` is expected, for example, when calling `flatMap` on a collection (or inside a for-comprehension)
 
-```
-scala> for {
-     |   a <- Set(1)
-     |   b <- Option(41)
-     | } yield (a + b)
-val res0: scala.collection.immutable.Set[Int] = Set(42)
+```scala mdoc
+for {
+  a <- Set(1)
+  b <- Option(41)
+} yield (a + b)
 ``` 
 
 since the operation `flatMap` on the type `Set[Int]` takes a function returning an `IterableOnce`: