Create subclass intention implemented #KT-8473 Fixed

Can be used for implementing interfaces / abstract classes / sealed classes or extending open classes

idea/testData/quickfix/implement/sealed.kt.after

@@ -0,0 +1,11 @@
+// "Implement sealed class" "true"
+// SHOULD_BE_AVAILABLE_AFTER_EXECUTION
+
+sealed class Base {
+    abstract fun foo(): Int
+    class BaseImpl : Base() {
+        override fun foo(): Int {
+            throw UnsupportedOperationException()
+        }
+    }
+}