Code typo fix

userscript.js

@@ -42,7 +42,7 @@ function getAllDocuments () {
     let childNodes = rootNode.childNodes;
     childNodes.forEach((childNode) => {
         // If the elements are documents they should not have an id.
-        if (childNode.getAttibute("id") === null) {
+        if (childNode.getAttribute("id") === null) {
             let child = childNode.firstChild;
             allDocuments.push(child);
         }