Clean up sign-in grammar

ash/ash_strings.grd

 <?xml version="1.0" encoding="UTF-8"?>
 
 <!--
 This file contains the strings for ash.
 -->
 
 <grit base_dir="." latest_public_release="0" current_release="1"
       source_lang_id="en" enc_check="möl">
   <outputs>
     <output filename="grit/ash_strings.h" type="rc_header">
@@ skipping 237 matching lines @@
       <message name="IDS_ASH_STATUS_TRAY_SMS_MESSAGES" desc="The label used in the default status tray view for SMS with the number of messages.">
         SMS messages: <ph name="MESSAGE_COUNT">$1<ex>3</ex></ph>
       </message>
       <message name="IDS_ASH_STATUS_TRAY_SMS_NUMBER" desc="Sender for SMS messagees in the system tray.">
         SMS from <ph name="PHONE_NUMBER">$1<ex>08700 776655</ex></ph>
       </message>
       <message name="IDS_ASH_STATUS_TRAY_SIGN_IN_ANOTHER_ACCOUNT" desc="The string for the button which lets the user add another account to the current session.">
         Sign in another account...
       </message>
       <message name="IDS_ASH_STATUS_TRAY_CAPTION_CANNOT_ADD_USER" desc="The caption for the error message when the user has reached the limit of multi profile users.">
-        Can't sign into another account.
+        Can't sign in to another account.
       </message>
       <message name="IDS_ASH_STATUS_TRAY_MESSAGE_CANNOT_ADD_USER" desc="The error message when the user has reached the limit of multi profile users.">
         You can only have up to three accounts in multiple sign-in.
       </message>
 
       <message name="IDS_ASH_STATUS_TRAY_BLUETOOTH" desc="The label used as the header in the bluetooth popup.">
         Bluetooth
       </message>
       <message name="IDS_ASH_STATUS_TRAY_BLUETOOTH_ENABLED" desc="The label used in the tray popup to notify that bluetooth is enabled.">
         Bluetooth enabled
@@ skipping 347 matching lines @@
 
       <!-- ChromeOS-specific strings -->
       <if expr="pp_ifdef('chromeos')">
         <part file="ash_chromeos_strings.grdp" />
       </if>
 
     </messages>
   </release>
 </grit>