jetty-dir.css not found when using JPMS #5488

Jetty version
9.4.x

Description
jetty-dir.css provides a minimal CSS for directory listing.
It resides in the jetty-util module.

When running Jetty with --jpms, a directory listing page will request jetty-dir.css but a 404 is returned.

My guess is that because of JPMS, the file won't be found unless module jetty.util opens its resources to jetty-servlet, which is probably the module that attempts to load it from the class-path.
If that's the case, jetty-dir.css should be moved to jetty-servlet.

A jetty-home test would be great.