Report a separate diagnostic on inheritance from singletons

compiler/testData/diagnostics/tests/enum/inheritFromEnumEntry.kt

@@ -0,0 +1,5 @@
+enum class E {
+    ENTRY
+}
+
+class A : <!SINGLETON_IN_SUPERTYPE!>E.ENTRY<!>

compiler/testData/diagnostics/tests/objects/Objects.kt

@@ -14,7 +14,7 @@ package toplevelObjectDeclarations
     }
   }
 
-  object B : <!SUPERTYPE_NOT_INITIALIZED, FINAL_SUPERTYPE!>A<!> {}
+  object B : <!SINGLETON_IN_SUPERTYPE!>A<!> {}
 
   val x = A.foo()
 

compiler/testData/diagnostics/tests/objects/ObjectsInheritance.kt

@@ -1,6 +1,5 @@
-
 package toplevelObjectDeclarations
 
 object CObj {}
 
-object DOjb : <!SUPERTYPE_NOT_INITIALIZED, FINAL_SUPERTYPE!>CObj<!> {}
+object DOjb : <!SINGLETON_IN_SUPERTYPE!>CObj<!> {}

compiler/testData/diagnostics/tests/scopes/ImportObjectAndUseAsSupertype.kt

@@ -12,7 +12,7 @@ package baz
 
 import foo.Bar
 
-class C: <!SUPERTYPE_NOT_INITIALIZED, FINAL_SUPERTYPE!>Bar<!>
+class C: <!SINGLETON_IN_SUPERTYPE!>Bar<!>
 
 fun test() {
     Bar.bar()