code: func (p *Namespaces) ShortIRI(iri string) string {
  	if !p.Safe {
  		p.mu.RLock()
  		defer p.mu.RUnlock()
  	}
  	for pref, ns := range p.prefixes {
  		if strings.HasPrefix(iri, ns) {
  			return pref + iri[len(ns):]
  		}
  	}
  	return iri
  }
docs: // ShortIRI replaces a base IRI of a known vocabulary with it's prefix.
  //
  //	ShortIRI("http://www.w3.org/1999/02/22-rdf-syntax-ns#type") // returns "rdf:type"