script: Move HTML DOM interfaces to script/dom/html/ (#39046)

See #38901.

Testing: Refactor
Fixes: Partially #38901

Signed-off-by: Ashwin Naren <arihant2math@gmail.com>

components/script/dom/html/htmlunknownelement.rs

@@ -0,0 +1,48 @@
+/* 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 https://mozilla.org/MPL/2.0/. */
+
+use dom_struct::dom_struct;
+use html5ever::{LocalName, Prefix};
+use js::rust::HandleObject;
+
+use crate::dom::bindings::root::DomRoot;
+use crate::dom::document::Document;
+use crate::dom::html::htmlelement::HTMLElement;
+use crate::dom::node::Node;
+use crate::script_runtime::CanGc;
+
+#[dom_struct]
+pub(crate) struct HTMLUnknownElement {
+    htmlelement: HTMLElement,
+}
+
+impl HTMLUnknownElement {
+    fn new_inherited(
+        local_name: LocalName,
+        prefix: Option<Prefix>,
+        document: &Document,
+    ) -> HTMLUnknownElement {
+        HTMLUnknownElement {
+            htmlelement: HTMLElement::new_inherited(local_name, prefix, document),
+        }
+    }
+
+    #[cfg_attr(crown, allow(crown::unrooted_must_root))]
+    pub(crate) fn new(
+        local_name: LocalName,
+        prefix: Option<Prefix>,
+        document: &Document,
+        proto: Option<HandleObject>,
+        can_gc: CanGc,
+    ) -> DomRoot<HTMLUnknownElement> {
+        Node::reflect_node_with_proto(
+            Box::new(HTMLUnknownElement::new_inherited(
+                local_name, prefix, document,
+            )),
+            document,
+            proto,
+            can_gc,
+        )
+    }
+}