Auto merge of #24220 - rasviitanen:domstringlist, r=jdm

add webidl bindings for DOMStringList

<!-- Please describe your changes on the following line: -->
To prepare for the implementation of `IndexedDB` a DOM interface for `DOMStringList` is added.

This change:
* Adds a new IDL file for `DOMStringList`
* Lists `domstringlist.rs` in `mod.rs`
* Defines a new DOMStruct `DOMStringList`
* Changes some test expectations related to `DOMStringList`
---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `___` with appropriate data: -->
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #24208

- [X] These changes do not require tests because:
We are not yet able to fully test the functions of `DOMStringList` in the WPT, because it is not possible to create an object of the type `DOMStringList` until e.g. `indexeddb` or `location.ancestorOrigins` is implemented.

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tests/wpt/mozilla/meta/MANIFEST.json

@@ -18959,7 +18959,7 @@
    "testharness"
   ],
   "mozilla/interfaces.html": [
-   "f30dd3de4087a45476745c4a41dd6a5f7e9365e3",
+   "7aed97b42d8fe974ea489db66905d9fbc0edb84d",
    "testharness"
   ],
   "mozilla/interfaces.js": [
@@ -18967,7 +18967,7 @@
    "support"
   ],
   "mozilla/interfaces.worker.js": [
-   "d14b58eb87568f05c398ae6953d4a0c17943219b",
+   "802fe64ebfc86480f3c5adc80718f550d09d330b",
    "testharness"
   ],
   "mozilla/invalid-this.html": [

tests/wpt/mozilla/tests/mozilla/interfaces.html

@@ -69,8 +69,9 @@ test_interfaces([
   "DOMException",
   "DOMImplementation",
   "DOMParser",
-  "DOMTokenList",
+  "DOMStringList",
   "DOMStringMap",
+  "DOMTokenList",
   "Element",
   "ErrorEvent",
   "Event",

tests/wpt/mozilla/tests/mozilla/interfaces.worker.js

@@ -18,6 +18,7 @@ test_interfaces([
   "DOMQuad",
   "DOMRect",
   "DOMRectReadOnly",
+  "DOMStringList",
   "CustomEvent",
   "DedicatedWorkerGlobalScope",
   "DOMException",