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

#KT-13298 Fixed

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

@@ -0,0 +1,27 @@
+interface I {
+    fun foo()
+    val someVal: Int
+    var someVar: Int
+}
+
+class Base1 {
+    protected open fun bar(){}
+}
+
+open class Base2 : Base1() {
+}
+
+class A : Base2(), I {
+    fun x() {
+        unresolved1(unresolved2)
+    }
+
+    override fun <caret>
+}
+
+// EXIST: { itemText: "override fun bar() {...}", lookupString: "bar", tailText: null, typeText: "Base1", attributes: "" }
+// EXIST: { itemText: "override fun foo() {...}", lookupString: "foo", tailText: null, typeText: "I", attributes: "bold" }
+// EXIST: { itemText: "override operator fun equals(other: Any?): Boolean {...}", lookupString: "equals", tailText: null, typeText: "Any", attributes: "" }
+// EXIST: { itemText: "override fun hashCode(): Int {...}", lookupString: "hashCode", tailText: null, typeText: "Any", attributes: "" }
+// EXIST: { itemText: "override fun toString(): String {...}", lookupString: "toString", tailText: null, typeText: "Any", attributes: "" }
+// NOTHING_ELSE