add Rob's 6WJC example

src/viewer/index.html

@@ -299,6 +299,17 @@
                     props: {
                         kind: 'membrane'
                     }
+                },
+                {
+                    id: '6WJC',
+                    info: 'ligand validation: Muscarinic acetylcholine receptor 1 - muscarinic toxin 7 complex: Focus + Density',
+                    props: {
+                        kind: 'feature-density',
+                        target: {
+                            label_asym_id: 'D',
+                            auth_seq_id: 502
+                        }
+                    }
                 }
             ];