LibWeb: Implement HTMLTableRowElement.deleteCell

Author: https://github.com/Lubrsi
Commit: 009f04fa46
Pull-request: https://github.com/SerenityOS/serenity/pull/15964
Reviewed-by: https://github.com/awesomekling

Userland/Libraries/LibWeb/HTML/HTMLTableRowElement.idl

@@ -18,4 +18,5 @@ interface HTMLTableRowElement : HTMLElement {
 
     [SameObject] readonly attribute HTMLCollection cells;
     HTMLTableCellElement insertCell(optional long index = -1);
+    [CEReactions] undefined deleteCell(long index);
 };