Fix up sentence structure in core review/TBR section.

Change-Id: If511b749a2231c6e3c5f500ed574f2229d02e389
Reviewed-on: https://chromium-review.googlesource.com/812325Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Commit-Queue: Alex Vallee <avallee@chromium.org>
Cr-Commit-Position: refs/heads/master@{#522456}

docs/code_reviews.md

@@ -110,7 +110,7 @@ review the change. If there are comments after landing, the author is obligated
 to address them in a followup patch.
 
 Do not use TBR just because a change is urgent or the reviewer is being slow.
-Contact the reviewer directly or find somebody.
+Contact the reviewer directly or find somebody else to review your change.
 
 To send a change TBR, annotate the description and send email like normal.
 Otherwise the reviewer won't know to review the patch.