Auto merge of #21856 - zcorpan:zcorpan/remove-td-th-interfaces, r=jdm

Remove the HTMLTable{Header,Data}CellElement interfaces

Fixes #17222.

<!-- Please describe your changes on the following line: -->
This removes the `HTMLTableHeaderCellElement` and `HTMLTableDataCellElement` interfaces and uses the `HTMLTableCellElement` interface for both `th` and `td` elements, as per the spec.

---
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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 #17222.

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- [X] There are tests for these changes OR
- [ ] These changes do not require tests because _____

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components/script/dom/webidls/HTMLTableCellElement.webidl

@@ -3,7 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 // https://html.spec.whatwg.org/multipage/#htmltablecellelement
-[HTMLConstructor, Abstract]
+[HTMLConstructor]
 interface HTMLTableCellElement : HTMLElement {
   [CEReactions]
            attribute unsigned long colSpan;
@@ -13,6 +13,11 @@ interface HTMLTableCellElement : HTMLElement {
   //          attribute DOMString headers;
   readonly attribute long cellIndex;
 
+  // [CEReactions]
+  //          attribute DOMString scope; // only conforming for th elements
+  // [CEReactions]
+  //          attribute DOMString abbr;  // only conforming for th elements
+
   // also has obsolete members
 };
 

components/script/dom/webidls/HTMLTableDataCellElement.webidl

@@ -1,15 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-// https://html.spec.whatwg.org/multipage/#htmltabledatacellelement
-[HTMLConstructor]
-interface HTMLTableDataCellElement : HTMLTableCellElement {
-  // also has obsolete members
-};
-
-// https://html.spec.whatwg.org/multipage/#HTMLTableDataCellElement-partial
-partial interface HTMLTableDataCellElement {
-  // [CEReactions]
-  //         attribute DOMString abbr;
-};

components/script/dom/webidls/HTMLTableHeaderCellElement.webidl

@@ -1,15 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-// https://html.spec.whatwg.org/multipage/#htmltableheadercellelement
-[HTMLConstructor]
-interface HTMLTableHeaderCellElement : HTMLTableCellElement {
-  // [CEReactions]
-  //         attribute DOMString scope;
-  // [CEReactions]
-  //         attribute DOMString abbr;
-  // [CEReactions]
-  //         attribute DOMString sorted;
-  // void sort();
-};