Auto merge of #25499 - NeverHappened:implement-form-dirname, r=jdm

Implement dirname support for form element

Added support for dirname in input on form submit
Added Dir getter / setter for HTMLElement
NOT YET Added get directionality according to https://html.spec.whatwg.org/multipage/dom.html#the-directionality

- [X] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix #25379 (GitHub issue number if applicable)

components/script/dom/webidls/HTMLElement.webidl

@@ -14,8 +14,8 @@ interface HTMLElement : Element {
            attribute DOMString lang;
   [CEReactions]
            attribute boolean translate;
-  // [CEReactions]
-  //         attribute DOMString dir;
+  [CEReactions]
+           attribute DOMString dir;
   readonly attribute DOMStringMap dataset;
 
   // microdata

components/script/dom/webidls/HTMLTextAreaElement.webidl

@@ -13,8 +13,8 @@ interface HTMLTextAreaElement : HTMLElement {
   //          attribute boolean autofocus;
   [CEReactions, SetterThrows]
            attribute unsigned long cols;
-  // [CEReactions]
-  //          attribute DOMString dirName;
+  [CEReactions]
+           attribute DOMString dirName;
   [CEReactions]
            attribute boolean disabled;
   readonly attribute HTMLFormElement? form;