Implement "Override hierarchy" view

idea/testData/hierarchy/overrides/javaMethodInClass/main0.java

@@ -0,0 +1,30 @@
+class A {
+    public void <caret>foo() {
+
+    }
+}
+
+class B extends A {
+    @Override
+    public void foo() {
+
+    }
+}
+
+class C implements T {
+    @Override
+    public void foo() {
+
+    }
+}
+
+class D extends Z {
+    @Override
+    public void foo() {
+
+    }
+}
+
+class S {
+
+}