Editorial: fix broken setAttribute link

(The link had been broken since it was added back in 2020
in e4bb7fe.)

source

@@ -3155,7 +3155,7 @@ a.setAttribute('href', 'https://example.com/'); // change the content attribute
      <li><dfn data-x="dom-Document-importNode" data-x-href="https://dom.spec.whatwg.org/#dom-document-importnode"><code>importNode()</code></dfn> method</li>
      <li><dfn data-x="dom-Event-preventDefault" data-x-href="https://dom.spec.whatwg.org/#dom-event-preventdefault"><code>preventDefault()</code></dfn> method</li>
      <li><dfn data-x="dom-Element-id" data-x-href="https://dom.spec.whatwg.org/#dom-element-id"><code>id</code></dfn> attribute</li>
-     <li><dfn data-x="dom-Element-setAttribute" data-x-href="https://dom.spec.whatwg.org/#dom-element-setAttribute"><code>setAttribute()</code></dfn> method</li>
+     <li><dfn data-x="dom-Element-setAttribute" data-x-href="https://dom.spec.whatwg.org/#dom-element-setattribute"><code>setAttribute()</code></dfn> method</li>
      <li><dfn data-x-href="https://dom.spec.whatwg.org/#dom-node-textcontent"><code>textContent</code></dfn> attribute</li>
 
      <li>The <dfn data-x-href="https://dom.spec.whatwg.org/#concept-tree">tree</dfn>, <dfn data-x-href="https://dom.spec.whatwg.org/#concept-shadow-tree">shadow tree</dfn>, and <dfn data-x-href="https://dom.spec.whatwg.org/#concept-node-tree">node tree</dfn> concepts</li>