Bug 264477: Use proper minus character for XML document tree display

r=sicking, sr=bzbarsky

content/xml/document/resources/XMLPrettyPrint.xml

@@ -65,7 +65,7 @@
           if (par.nodeName == 'td' && par.className == 'expander') {
             if (par.parentNode.className == 'expander-closed') {
               par.parentNode.className = '';
-              event.originalTarget.firstChild.data = '-';
+              event.originalTarget.firstChild.data = '\u2212';
             }
             else {
               par.parentNode.className = 'expander-closed';

content/xml/document/resources/XMLPrettyPrint.xsl

@@ -157,7 +157,7 @@
   </xsl:template>
   
   <xsl:template name="expander">
-    <td class="expander">-<div class="spacer"/></td>
+    <td class="expander">&#x2212;<div class="spacer"/></td>
   </xsl:template>
 
 </xsl:stylesheet>