Old backing field with dollar is now forbidden

idea/testData/checker/AnonymousInitializers.kt

@@ -13,7 +13,7 @@ interface NoC {
 class WithC() {
   val x : Int
   init {
-    <warning descr="[BACKING_FIELD_USAGE_DEPRECATED] Backing field usage is deprecated here, soon it will be possible only in property accessors">$x</warning> = 1
+    <error>$x</error> = 1
     <error>$y</error> = 2
     val <warning>b</warning> = x
 

idea/testData/checker/Constructors.kt

@@ -28,7 +28,7 @@ class WithCPI_Dup(<warning>x</warning> : Int) {
 
 class WithCPI(x : Int) {
   val a = 1
-  val b : Int = <warning descr="[BACKING_FIELD_USAGE_DEPRECATED] Backing field usage is deprecated here, soon it will be possible only in property accessors">$a</warning>
+  val b : Int = <error>$a</error>
   val xy : Int = x
 }
 

idea/testData/checker/regression/Jet17.kt

@@ -2,5 +2,5 @@
 
 class WithC() {
   val a = 1
-  val b = <warning descr="[BACKING_FIELD_USAGE_DEPRECATED] Backing field usage is deprecated here, soon it will be possible only in property accessors">$a</warning> // error here, but must not be
+  val b = <error>$a</error> // error here, but must not be
 }