Cosmetic update to finddialog.xul and dtd. r=syd

xpfe/components/find/resources/locale/en-US/finddialog.dtd

@@ -1,7 +1,7 @@
 <!-- extracted from finddialog.xul -->
 
 <!ENTITY findDialog.title "Find on Page">
-<!ENTITY findField.label "Find:">
+<!ENTITY findField.label "Find Text:">
 <!ENTITY caseSensitiveCheckbox.label "Case Sensitive">
 <!ENTITY wrapCheckbox.label "Wrap">
 <!ENTITY backwardsCheckbox.label "Backwards">