KT-13298 Suggest names for overridden properties / functions in completion

#KT-13298 Fixed

idea/idea-completion/testData/basic/common/override/NoOverrideAfterFunKeyword.kt

@@ -0,0 +1,10 @@
+interface I {
+    fun ov_foo()
+}
+
+class A : I {
+    override fun ov<caret>
+}
+
+// ABSENT: override
+// EXIST: { itemText: "override fun ov_foo() {...}", allLookupStrings: "ov_foo", tailText: null, typeText: "I", attributes: "bold" }