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

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="chromeos">. -->
 <grit-part>
   <message name="IDS_EMPTY_STRING" desc="Empty string, exist only to make code generic. No translation required.">
   </message>
   <message name="IDS_CHROMEBOOK" desc="The localized name for Chromebook.">
     Chromebook
   </message>
   <message name="IDS_CHROMEBOX" desc="The localized name for Chromebox">
@@ skipping 2003 matching lines @@
   </message>
   <message name="IDS_OPTIONS_SETTINGS_BLUETOOTH_CONNECT_UNSUPPORTED_DEVICE">
     Unsupported Bluetooth device: "<ph name="DEVICE_NAME">%1<ex>Nexus 4</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.">
+  <message name="IDS_OPTIONS_SETTINGS_ACCESSIBILITY_EXPLANATION" desc="In the settings tab, this text explains the accessibility features.">
     Enable accessibility features to make your device easier to use.
   </message>
   <message name="IDS_OPTIONS_SETTINGS_ACCESSIBILITY_SETTINGS" desc="Text of the link to open ChromeVox settings.">
     Settings
   </message>
   <message name="IDS_OPTIONS_SETTINGS_ACCESSIBILITY_LARGE_CURSOR_DESCRIPTION" desc="In the settings tab, the text next to the checkbox for the large mouse cursor.">
     Show large mouse cursor
   </message>
   <message name="IDS_OPTIONS_SETTINGS_ACCESSIBILITY_SPOKEN_FEEDBACK_DESCRIPTION" desc="In the settings tab, the text next to the checkbox for spoken feedback.">
     Enable ChromeVox (spoken feedback)
@@ skipping 3946 matching lines @@
   <message name="IDS_SET_TIME_BUTTON_CLOSE" desc="Text for the button to close the window.">
     Done
   </message>
   <message name="IDS_SET_TIME_DATE_LABEL" desc="Label for the date input element.">
     System date
   </message>
   <message name="IDS_SET_TIME_TIME_LABEL" desc="Label for the time input element.">
     System time
   </message>
 </grit-part>