mailmap: Consolidate some original Zulip authors.

I expect this will fix them appearing as duplicates.

.mailmap

@@ -1,11 +1,17 @@
 Aman Agrawal <[email protected]>
 Anders Kaseorg <[email protected]> <[email protected]>
 Anders Kaseorg <[email protected]> <[email protected]>
+Jessica McKellar <[email protected]> <[email protected]>
+Luke Faraone <[email protected]> <[email protected]>
 Rishi Gupta <[email protected]> <[email protected]>
 Steve Howell <[email protected]> <[email protected]>
 Steve Howell <[email protected]> <[email protected]>
 Steve Howell <[email protected]> <[email protected]>
 Tim Abbott <[email protected]> <[email protected]>
 Tim Abbott <[email protected]> <[email protected]>
 Tim Abbott <[email protected]> <[email protected]>
+Zev Benjamin <[email protected]> <[email protected]>
+Zev Benjamin <[email protected]> <[email protected]>
+Zev Benjamin <[email protected]> <[email protected]>
+Zev Benjamin <[email protected]> <[email protected]>
 Zixuan James Li <[email protected]> <[email protected]>