add localized strings for Inbox/Drafts/etc as preparation for 18364/37183/33852

r=sspitzer

mailnews/base/resources/locale/en-US/messenger.properties

@@ -65,3 +65,21 @@ serverType-movemail=Unix Movemail
 recipientColumnHeader=Recipient
 senderColumnHeader=Sender
 
+# status feedback stuff
+documentDonePrefix=Document: Done (
+documentDonePostfix=secs)
+documentDone=Document: Done
+documentLoading=Loading Document...
+
+# localized folder names
+
+localFolders=Local Folders
+
+unsentFolderName=Unsent Messages
+
+inboxFolderName=Inbox
+trashFolderName=Trash
+sentFolderName=Sent
+draftsFolderName=Drafts
+templatesFolderName=Templates
+unsentFolderName=Unsent Messages