Rewrite mutable.{Map, Set}.+ corner case

Author: MasseGuillaume

scalafix/input/src/main/scala/fix/MutSetMapSrc.scala

@@ -8,4 +8,5 @@ import scala.collection.mutable
 class MutSetMapSrc(map: mutable.Map[Int, Int], set: mutable.Set[Int]) {
   set + 2
   map + (2 -> 3)
+  (set + 2).size
 }

scalafix/output/src/main/scala/fix/MutSetMapSrc.scala

@@ -8,4 +8,5 @@ import scala.collection.mutable
 class MutSetMapSrc(map: mutable.Map[Int, Int], set: mutable.Set[Int]) {
   set.clone() += 2
   map.clone() += (2 -> 3)
+  (set.clone() += 2).size
 }