Old backing field with dollar is now forbidden

idea/testData/refactoring/rename/renameFieldIdentifier/after/test.kt

@@ -1,6 +1,6 @@
 class Exp(p1: String) {
     val /*rename*/prop11: String = p1
         get(): String {
-            return $prop11
+            return field
         }
 }

idea/testData/refactoring/rename/renameFieldIdentifier/before/test.kt

@@ -1,6 +1,6 @@
 class Exp(p1: String) {
     val /*rename*/prop1: String = p1
         get(): String {
-            return $prop1
+            return field
         }
 }