fixes #1012 - typo in css-parts documentation

Author: mrin9

docs/css-parts.html

@@ -258,7 +258,7 @@ <h2>CSS Parts</h2>
         <tr>
           <td class="mono">
             label-header-title, label-overview-title, label-selected-server, label-tag-title, 
-            label-operations-method, label-operation-path
+            label-operation-method, label-operation-path
           </td>
         </tr>