Implement rendering of raw types

Also add some clarification in spec

idea/testData/codeInsight/overrideImplement/implementJavaRawSubclass/foo/Impl.kt.after

@@ -0,0 +1,8 @@
+import foo.A
+import foo.B
+
+class C : A() {
+    override fun foo(x: MutableList<Any?>?, y: String?): B<*>? {
+        <selection><caret>throw UnsupportedOperationException()</selection>
+    }
+}