[CrOS MultiDevice] Update string in multi-device setup flow.

This suggestion was provided by the UX team.

Bug: 824568
Change-Id: I2728b1e1de4b0d8c27c13f0f70eb5eed80f6029f
Reviewed-on: https://chromium-review.googlesource.com/1155904Reviewed-by: Jeremy Klein <jlklein@chromium.org>
Commit-Queue: Kyle Horimoto <khorimoto@chromium.org>
Cr-Commit-Position: refs/heads/master@{#579237}

chrome/app/chromeos_strings.grdp

@@ -183,8 +183,8 @@
   <message name="IDS_MULTIDEVICE_SETUP_START_SETUP_PAGE_INSTALL_APPS_DESCRIPTION" desc="Tell the user that Better Together can install apps on their Chromebook">
     Install apps on your Chromebook
   </message>
-  <message name="IDS_MULTIDEVICE_SETUP_START_SETUP_PAGE_ADD_FEATURES" desc="Tell the user that Better Together can add new features to that use their phone's connection to their Chromebook">
-    Add new features that use your phone's connection to your Chromebook
+  <message name="IDS_MULTIDEVICE_SETUP_START_SETUP_PAGE_ADD_FEATURES" desc="Tell the user that Better Together can offer to add new features to that use their phone's connection to their Chromebook">
+    Offer new features that use your phone's connection to your Chromebook
   </message>
 
   <!-- MultiDevice 'Forget device' dialog -->