Convert to expression body: insert new-line after = for long lines

idea/testData/refactoring/extractFunction/basic/callableReferenceSelector.kt.after

@@ -10,6 +10,7 @@ class Foo {
             arguments = map(arg)
         }
 
-        private fun map(arg: String) = mapOf(Foo::arguments.name to arg)
+        private fun map(arg: String) =
+                mapOf(Foo::arguments.name to arg)
     }
 }