[MD settings] explain when no usb devices are shown in site settings

chrome/app/settings_strings.grdp

 <?xml version="1.0" encoding="utf-8"?>
 <!-- Settings-specific strings (included from generated_resources.grd). -->
 <grit-part>
   <!-- Main Page -->
   <if expr="chromeos">
     <message name="IDS_SETTINGS_SECONDARY_USER_BANNER" desc="Banner displayed in settings page when the user is secondary in a multi-profile session.">
       Some settings belonging to <ph name="PRIMARY_EMAIL">$1<ex>john@google.com</ex></ph> are being shared with you. These settings only affect your account when using multiple sign-in.
     </message>
   </if>
 
@@ skipping 915 matching lines @@
     </message>
     <message name="IDS_SETTINGS_PRINTING_CUPS_PRINTER_ADVANCED_ADDRESS" desc="Label for the CUPS printer address in the Advanced section in the printer details page.">
       Address
     </message>
     <message name="IDS_SETTINGS_PRINTING_CUPS_PRINTER_ADVANCED_PROTOCOL" desc="Label for the CUPS printer protocol in the Advanced section in the printer details page.">
       Protocol
     </message>
     <message name="IDS_SETTINGS_PRINTING_CUPS_PRINTER_ADVANCED_URI" desc="Label for the CUPS printer URI (uniform resource identifier) in the Advanced section in the printer details page.">
       URI
     </message>
-    <message name="IDS_SETTINGS_PRINTING_CUPS_PRINTER_DETAILS_NAME" desc="Lable for the CUPS printer name in the printer details page.">
+    <message name="IDS_SETTINGS_PRINTING_CUPS_PRINTER_DETAILS_NAME" desc="Label for the CUPS printer name in the printer details page.">
       Name
     </message>
     <message name="IDS_SETTINGS_PRINTING_CUPS_PRINTER_DETAILS_MODEL" desc="Label for the CUPS printer model in the printer details page.">
       Model
     </message>
     <message name="IDS_SETTINGS_PRINTING_CUPS_PRINTER_DETAILS_QUEUE" desc="Label for the CUPS printer queue in the manually add printer dialog.">
       Queue
     </message>
     <message name="IDS_SETTINGS_PRINTING_CUPS_ADD_PRINTER_BUTTON_CANCEL" desc="Text for the button which cancels adding a CUPS printer.">
       Cancel
@@ skipping 1240 matching lines @@
   </message>
   <message name="IDS_SETTINGS_SITE_SETTINGS_INCOGNITO_EMBEDDED" desc="A label for a site rule that specifies an embedded origin and only applies to the current incognito session.">
     Current incognito session (<ph name="EMBEDDING">$1<ex>embedded on google.com</ex></ph>)
   </message>
   <message name="IDS_SETTINGS_SITE_SETTINGS_NO_ZOOMED_SITES" desc="A label explaining that no sites have a configured zoom in/out value.">
     No sites have been zoomed in or out
   </message>
   <message name="IDS_SETTINGS_SITE_DETAILS" desc="A title for the site settings details subpage.">
     Site details
   </message>
-  <message name="IDS_SETTINGS_SITE_NO_SITES_ADDED" desc="Explenation for not showing a list of site exceptions">
+  <message name="IDS_SETTINGS_SITE_NO_SITES_ADDED" desc="Explanation for not showing a list of site exceptions">
     No sites added
   </message>
 
+  <message name="IDS_SETTINGS_NO_USB_DEVICES_FOUND" desc="Explanation for not showing USB devices in site settings.">
+    No USB devices found
+  </message>
   <message name="IDS_SETTINGS_ADD_SITE_EXCEPTION_PLACEHOLDER" desc="Placeholder text shown before the user starts typing a new content settings exception for a site." >
     [*.]example.com
   </message>
   <message name="IDS_SETTINGS_ADD_SITE_TITLE" desc="Title for the Add Site dialog">
     Add a site
   </message>
   <message name="IDS_SETTINGS_EDIT_SITE_TITLE" desc="Title for the Edit Site dialog">
     Edit site
   </message>
   <message name="IDS_SETTINGS_ADD_SITE" desc="The label for the input box for adding a site">
@@ skipping 874 matching lines @@
       System
     </message>
     <message name="IDS_SETTINGS_SYSTEM_HARDWARE_ACCELERATION_LABEL" desc="Label for the checkbox that forces Chrome to render via hardware acceleration (GPU) when available.">
       Use hardware acceleration when available
     </message>
     <message name="IDS_SETTINGS_SYSTEM_PROXY_SETTINGS_LABEL" desc="Label for the control that opens a user's network proxy settings.">
       Open proxy settings
     </message>
   </if>
 </grit-part>