Switch to data_url::mime for document content type (#36522)

The data_url Mime parser has a more conformant behavior in most cases,
including dealing with charsets.

Testing: wpt expectations with new passes are updated.

Signed-off-by: webbeef <me@webbeef.org>

components/script/lib.rs

@@ -48,6 +48,7 @@ pub mod layout_dom;
 #[allow(unsafe_code)]
 pub(crate) mod messaging;
 mod microtask;
+pub(crate) mod mime;
 mod navigation;
 mod network_listener;
 mod realms;