strings for newly exposed prefs (submitted by rcassin@supernova.org)

xpfe/components/prefwindow/resources/locale/en-US/pref-composer.dtd

@@ -29,3 +29,6 @@
 <!ENTITY  htmlSource                "HTML Source:">
 <!ENTITY  imageeditor               "Images:">
 <!ENTITY  chooseButton.label        "Choose">
+
+<!ENTITY  recentFiles.title         "Recently Edited Files Menu">
+<!ENTITY  documentsInMenu           "documents listed in Recent Files menu">