code: @DontLabel
      public final JoinMatcherBootstrap<V, BaseParser<V>> join(final Object rule)
      {
          final Rule matcher = toRule(rule);
          return new JoinMatcherBootstrap<>(this, matcher);
      }
docs: Kickstart a {@code join} rule
  
  <p>Usages:</p>
  
  <pre>
  return join(rule()).using(otherRule()).times(n);
  return join(rule()).using(otherRule()).min(n);
  </pre>
  
  <p>etc. See {@link JoinMatcherBuilder} for more possible constructs.</p>
  
  @param rule the joined rule (must not match an empty sequence!)
  @return a {@link JoinMatcherBootstrap}
  
  @see JoinMatcherBootstrap#using(Object)