use .text() instead of .html()

IPython/frontend/html/notebook/static/notebook/js/textcell.js

@@ -514,7 +514,7 b' var IPython = (function (IPython) {'
             $('<a/>')
                 .addClass('anchor-link')
                 .attr('href', '#' + link)
-                .html('¶')
+                .text('¶')
             )
         );
     };