Revert "Drop deprecated displayName from descriptor visibility"

This reverts commit 6fa11d1573.

core/descriptors/src/org/jetbrains/kotlin/descriptors/Visibility.kt

@@ -64,6 +64,14 @@ abstract class Visibility protected constructor(
     open val externalDisplayName: String
         get() = internalDisplayName
 
+    @Deprecated(
+        "Visibility.displayName is deprecated, use internalDisplayName instead",
+        ReplaceWith("internalDisplayName"),
+        level = DeprecationLevel.WARNING
+    )
+    open val displayName: String
+        get() = internalDisplayName
+
     override final fun toString() = internalDisplayName
 
     open fun normalize(): Visibility = this