Fix some minor typos related to the word "accessibility".

ash/ash_chromeos_strings.grdp

 <?xml version="1.0" encoding="utf-8"?>
 <!-- ChromeOS-specific strings (included from ash_strings.grd).
      Everything in this file is wrapped in <if expr="chromeos">. -->
 <grit-part>
 
   <!-- Status tray charging strings. -->
   <message name="IDS_ASH_STATUS_TRAY_LOW_POWER_CHARGER_TITLE" desc="The title of a notification indicating that a low-current USB charger has been connected.">
     Low-power charger connected
   </message>
   <message name="IDS_ASH_STATUS_TRAY_LOW_POWER_CHARGER_MESSAGE" desc="The message body of a notification indicating that a low-current USB charger has been connected.">
     Your Chromebook may not charge while it is turned on. Consider using the official charger.
   </message>
   <message name="IDS_ASH_STATUS_TRAY_LOW_POWER_CHARGER_MESSAGE_SHORT" desc="The message body of a notification indicating that a low-current USB charger has been connected, short version.">
     Your Chromebook may not charge while it is turned on.
   </message>
 
-  <message name="IDS_CHARGER_REPLACEMENT_ACCESSIBILTY_NOTIFICATION" desc="The notification string used in accessibility to tell user to contact Google for replacing the possible bad charger.">
+  <message name="IDS_CHARGER_REPLACEMENT_ACCESSIBILITY_NOTIFICATION" desc="The notification string used in accessibility to tell user to contact Google for replacing the possible bad charger.">
     You may have a bad charger. If you live in the US, please call 866-628-1371 in order to receive help and a replacement. If you live in the UK, please call 0800-026-0613. If you live in Ireland, please call 1-800-832-664. If you live in Canada, please call 866-628-1372. If you live in Australia, please call 1-800-067-460.
   </message>
 
   <!-- Status Tray Network strings -->
   <message name="IDS_ASH_STATUS_TRAY_NETWORK" desc="The label used in the network dialog header.">
     Network
   </message>
   <message name="IDS_ASH_STATUS_TRAY_VPN" desc="The label used in the VPN detailed view header.">
     Private Network
   </message>
@@ skipping 369 matching lines @@
   <message name="IDS_ASH_LOGOUT_CONFIRMATION_WARNING" desc="The text for the logout confirmation dialog.">
     You will automatically be signed out in <ph name="LOGOUT_TIME_LEFT">$1<ex>5 seconds</ex></ph>.
   </message>
   <message name="IDS_ASH_LOGOUT_CONFIRMATION_WARNING_NOW" desc="The text for the logout confirmation dialog with no time left.">
     You will be signed out now.
   </message>
   <message name="IDS_ASH_LOGOUT_CONFIRMATION_BUTTON" desc="The text for okay button of the logout confirmation dialog.">
     Sign out now
   </message>
 </grit-part>