Editorial: fix broken markup

fetch.bs

@@ -8878,7 +8878,7 @@ particular at what stage you would like to receive a callback:
   continues from there.
 
   <p>To process a <a for=/>response</a> chunk-by-chunk, pass an algorithm to the
-  <a for=fetch><i>processResponse</i></a> argument of <a for/>fetch</a>. The given
+  <a for=fetch><i>processResponse</i></a> argument of <a for=/>fetch</a>. The given
   algorithm is passed a <a for=/>response</a> when the response's headers have been
   received and is responsible for reading the <a for=/>response</a>'s
   <a for=response>body</a>'s <a for=body>stream</a> in order to download the rest