docs: def prefixedname_to_str(self, prefix: ShExDocParser.PrefixedNameContext) -> str:
          """ prefixedName: PNAME_LN | PNAME_NS
              PNAME_NS: PN_PREFIX? ':' ;
              PNAME_LN: PNAME_NS PN_LOCAL ;
          """
          if prefix.PNAME_NS():
              return self._lookup_prefix(prefix.PNAME_NS().getText())
          else:
              prefix, local = prefix.PNAME_LN().getText().split(':', 1)
              return self._lookup_prefix(prefix + ':') + (local if local else "")