[Standards] XEP-0338 (Jingle Grouping Framework): feedback requested on PR

Hello everybody, Council is evaluating the following PR which update the XEP-0388 (Jingle Grouping Framework), a stable XEP: https://github.com/xsf/xeps/pull/1567 It adds a large large text which is enforcing rules. The way as I get it, it's not breaking existing implementation and it enforces rules which is a good thing. However, this PR has probably been missed by most, so we would like to have feedback from wider community before approving it or not. Thanks! Goffi (on behalf of Council)