Improve documentation of the migration tool and fix the input and output files.

Author: julienrf

input/src/main/scala/fix/Collectionstrawman_v0.scala

@@ -53,7 +53,6 @@ object Collectionstrawman_v0_Range {
 }
 
 object Collectionstrawman_v0_Traversable {
-  val x: Iterable[String] = ???
   def foo(xs: Traversable[(Int, String)], ys: List[Int]): Unit = {
     xs.toList
     xs.toSet

output/src/main/scala/fix/Collectionstrawman_v0.scala

@@ -1,7 +1,10 @@
 package fix
 
-import strawman.collection.{ arrayToArrayOps, stringToStringOps }
-import strawman.collection.immutable.{ #::, ::, HashMap, LazyList, List, Map, Nil, Range, Vector }
+import scala.Predef.{augmentString => _, ArrowAssoc, charWrapper}
+
+import strawman.collection.{ Iterable, Set, arrayToArrayOps, stringToStringOps }
+import strawman.collection.immutable.{ ::, HashMap, LazyList, List, Map, Nil, Range, Vector }
+import strawman.collection.immutable.LazyList.#::
 import strawman.collection.mutable.ArrayBuffer
 
 object Collectionstrawman_v0_List {