Auto merge of #13081 - hsinewu:nodelist-iterable, r=Ms2ger

make nodeList iterable

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Not sure what to test in the script.
Need some advice. o_O

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- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #13021 (github issue number if applicable).

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- [X] There are tests for these changes

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components/script/dom/webidls/NodeList.webidl

@@ -12,5 +12,5 @@ interface NodeList {
   getter Node? item(unsigned long index);
   [Pure]
   readonly attribute unsigned long length;
-  // iterable<Node>;
+  iterable<Node?>;
 };