fix tooltip. the IM button does IM and Chat. a=jglick,robinf.

mailnews/addrbook/resources/locale/en-US/abMainWindow.dtd

@@ -95,7 +95,7 @@ Rights Reserved.
 <!ENTITY newlistButton.tooltip                          "Create a new list"> 
 <!ENTITY editButton.tooltip                             "Edit the selected card"> 
 <!ENTITY newmsgButton.tooltip                           "Send a mail message"> 
-<!ENTITY newIM.tooltip                                  "Send an instant message"> 
+<!ENTITY newIM.tooltip                                  "Send an instant message or chat"> 
 <!ENTITY deleteButton.tooltip                           "Delete selected card or address book"> 
 <!ENTITY stopButton.tooltip                             "Stop the current transfer"> 
 <!ENTITY searchButton.tooltip                           "Search the selected address book">