Add mahmadi@ to components/search/OWNERS

Also annotate other teammates relationships to this code.

R=mahmadi@chromium.org
BUG=none

Change-Id: I3eabc0422737c1ef0184fc554890308850ccb8a3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1854399Reviewed-by: Moe Ahmadi <mahmadi@chromium.org>
Commit-Queue: Dan Beam <dbeam@chromium.org>
Cr-Commit-Position: refs/heads/master@{#704851}

components/search/OWNERS

+# Incoming team
 dbeam@chromium.org
+mahmadi@chromium.org
+
+# Outgoing team
 gayane@chromium.org
 kmilka@chromium.org
 kristipark@chromium.org
-mathp@chromium.org
 ramyan@chromium.org
 
+# Former team
+mathp@chromium.org
+
 # Original implementors of most of the code, but not active in Chromium anymore:
 # - jered@chromium.org
 # - samarth@chromium.org