fix list of unsupported tags

A previous commit sourced the list of tag names
from an old HTML spec. The list has now been
updated following the HTML living spec.

https://html.spec.whatwg.org/#non-conforming-features

src/html/Ast.zig

@@ -35,12 +35,16 @@ const unsupported_names = TagNameMap.initComptime(.{
     .{ "frame", {} },
     .{ "frameset", {} },
     .{ "noframes", {} },
-    .{ "hgroup", {} },
     .{ "isindex", {} },
+    .{ "keygen", {} },
     .{ "listing", {} },
+    .{ "menuitem", {} },
     .{ "nextid", {} },
     .{ "noembed", {} },
+    .{ "param", {} },
     .{ "plaintext", {} },
+    .{ "rb", {} },
+    .{ "rtc", {} },
     .{ "strike", {} },
     .{ "xmp", {} },
     .{ "basefont", {} },