Making the key names in the mousewheel preferences dialog

platform-specific.  bug 23685, r=ben@netscape.com.

suite/common/pref/pref-mousewheel.xul

@@ -25,7 +25,13 @@
 
 <?xml-stylesheet href="chrome://pref/skin/" type="text/css"?>
   
-<!DOCTYPE window SYSTEM "chrome://pref/locale/pref-mousewheel.dtd" >
+<!DOCTYPE window [
+<!ENTITY % platformDTD SYSTEM "chrome://global/locale/platformDialogOverlay.dtd" >
+%platformDTD;
+<!ENTITY % prefMousewheelDTD SYSTEM "chrome://pref/locale/pref-mousewheel.dtd" >
+%prefMousewheelDTD;
+]>
+
 <window xmlns:html="http://www.w3.org/TR/REC-html40"
 		xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
     class="dialog"

suite/locales/en-US/chrome/common/pref/pref-mousewheel.dtd

@@ -4,12 +4,12 @@
 <!ENTITY info.label "Mouse Wheel Configuration">
 <!ENTITY mouseWheelPanel.label "When ">
 <!ENTITY usingJustTheWheel.label "using just the mouse wheel">
-<!ENTITY usingWheelAndAlt.label "using the wheel while pressing the Alt key">
-<!ENTITY usingWheelAndCtrl.label "using the wheel while pressing the Ctrl key">
-<!ENTITY usingWheelAndShft.label "using the wheel while pressing the Shift key">
+<!ENTITY usingWheelAndAlt.label "using the wheel while pressing the &altKey.label; key">
+<!ENTITY usingWheelAndCtrl.label "using the wheel while pressing the &ctrlKey.label; key">
+<!ENTITY usingWheelAndShft.label "using the wheel while pressing the &shiftKey.label; key">
 <!ENTITY scroll.label "Scroll the document by ">
 <!ENTITY scrollLines.label " lines. ">
 <!ENTITY useSystemDefault.label "Use system default.">
 <!ENTITY scrollPgUpPgDn.label "Scroll a page up or a page down">
 <!ENTITY history.label "Move back and forward in the browsing history">
-  
+