Add top alignment for wrapped <td>s

Author: benjaoming

sass/_theme_layout.sass

@@ -398,6 +398,8 @@ footer
 +media($desktop)
   .wy-table-responsive table td
     white-space: normal
+  .rst-content table.docutils td
+    vertical-align: top
 
 +media($desktop-wider)
   .wy-nav-content-wrap