Fix typo

Bug: none
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: Ifc43afb495541b7ed62e9d001d331469d3156caa
Reviewed-on: https://chromium-review.googlesource.com/776694Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Commit-Queue: Louis Romero <lpromero@chromium.org>
Cr-Commit-Position: refs/heads/master@{#517434}

ios/PRESUBMIT.py

@@ -57,5 +57,5 @@ def PostUploadHook(cl, change, output_api):
               'master.tryserver.chromium.mac:ios-simulator-full-configs']
 
   return output_api.EnsureCQIncludeTrybotsAreAdded(
-    cl, try_bots, 'Automatically added Cronet and EarlGrey trybots to'
+    cl, try_bots, 'Automatically added Cronet and EarlGrey trybots to '
       'run tests on CQ.')