search: fix typo in comment (ISO 639 not 693).
search: fix typo in comment (ISO 639 not 693).

Change-Id: I8f360c9e72b3177bbbcd97aabad92dcf71798c40

golang/appengine,fuchsia-mirror/third_party-github.com-golang-appengine,golang/appengine,fuchsia-mirror/third_party-github.com-golang-appengine