CDDL comma use alignment

[akeranen]

CDDL for the spec is sometimes using a comma in the groups and sometimes (most of the time) not. For example:

thingqualities = {
 commonqualities,
 ? sdfObject: named<objectqualities>
 ? sdfThing: named<thingqualities>
 EXTENSION-POINT<"thing-ext">
}

While syntactically OK, for consistent style would be good to align this.