void resolveReferenced(ParsedDocument parsed) {
        var old = resolvedReferences.put(parsed.name(), parsed);
        assert(old == null || old == parsed);
    }
This class holds the extracted information after parsing a
"document" block in a schema (.sd) file, using simple data
structures as far as possible.  Do not put advanced logic here!
@author arnej27959
config-model/src/main/java/com/yahoo/schema/parser/ParsedDocument.java