`rdfdiff` with quad support

### Version

4.9.0

### Feature

[`rdfdiff`](https://github.com/apache/jena/blob/main/jena-cmds/src/main/java/arq/rdfdiff.java) only supports triples.
Is there a reason why it couldn't support quads as well?

### Are you interested in contributing a solution yourself?

Perhaps?

Start with jena-cmds/src/main/java/arq/rdfdiff.java, the entry point named in the issue, and trace how rdfdiff currently handles triples. Determine the required behavior for quads and verify that rdfdiff can compare quad data as well as triples.

Written by the indexing model from the issue text.