Adding learn more link in chrome://settings for a11y features

chrome/app/chromeos_strings.grdp

 <?xml version="1.0" encoding="utf-8"?>
 <!-- ChromeOS-specific strings (included from generated_resources.grd).
      Everything in this file is wrapped in <if expr="pp_ifdef('chromeos')">. -->
 <grit-part>
   <!-- Idle Logout Dialog Strings -->
   <message name="IDS_IDLE_LOGOUT_TITLE" desc="Dialog title for the idle logout dialog">
     Are you still there?
   </message>
   <message name="IDS_IDLE_LOGOUT_WARNING_RESTART" desc="Restart label for the idle logout dialog">
     This computer will reset in <ph name="LOGOUT_TIME_LEFT">$1<ex>20</ex></ph> seconds.
@@ skipping 685 matching lines @@
   </message>
   <message name="IDS_OPTIONS_SETTINGS_BLUETOOTH_CONNECT_FAILED">
     Failed to connect to "<ph name="DEVICE_NAME">%1<ex>Nexus S</ex></ph>".
   </message>
   <message name="IDS_OPTIONS_SETTINGS_BLUETOOTH_DISCONNECT_FAILED">
     Failed to disconnect from "<ph name="DEVICE_NAME">%1<ex>Nexus S</ex></ph>".
   </message>
   <message name="IDS_OPTIONS_SETTINGS_BLUETOOTH_FORGET_FAILED">
     Failed to disconnect and unpair from "<ph name="DEVICE_NAME">%1<ex>Nexus S</ex></ph>".
   </message>
+  <message name="IDS_OPTIONS_SETTINGS_ACCESSIBILITY_EXPLANATION" desc="In the settings tab, this text explains the accessibiliy features.">
+    Enable the accessibility features you need.
+  </message>
   <message name="IDS_OPTIONS_SETTINGS_ACCESSIBILITY_DESCRIPTION" desc="In the settings tab, the text next to the checkbox for spoken feedback.">
     Enable spoken feedback
   </message>
   <message name="IDS_OPTIONS_SETTINGS_ACCESSIBILITY_HIGH_CONTRAST_DESCRIPTION" desc="In the settings tab, the text next to the checkbox for high contrast mode.">
     Enable high contrast mode
   </message>
   <message name="IDS_OPTIONS_SETTINGS_ACCESSIBILITY_SCREEN_MAGNIFIER_DESCRIPTION" desc="In the settings tab, the text next to the dropdown for screen magnifier.">
     Enable screen magnifier
   </message>
   <message name="IDS_OPTIONS_SETTINGS_ACCESSIBILITY_SCREEN_MAGNIFIER_OFF" desc="In the settings tab, the option indication the screen magnifier is off.">
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   <message name="IDS_LOGIN_MANAGED_BY_STATUS_NETWORK_ERROR" desc="Text for the network error status in 'Managed by DOMAIN' label on login screen.">
     Network error while communicating with the device management service.
   </message>
   <message name="IDS_LOGIN_MANAGED_BY_NOTICE" desc="Text for the notification bar on the login screen showing that this is a managed device.">
     This device is managed by <ph name="DOMAIN">$1<ex>yourdomain.com</ex></ph>.
   </message>
   <message name="IDS_LOGIN_MANAGED_REPORTING_HINT" desc="Text for the hint on reporting features displayed in the enterprise notification bar on the login screen.">
     Device usage may be tracked.
   </message>
 </grit-part>