code: public Router head(@NotNull final String pattern, @NotNull final Handler<YokeRequest> handler) {
          return head(pattern, new Middleware() {
              @Override
              public void handle(@NotNull YokeRequest request, @NotNull Handler<Object> next) {
                  handler.handle(request);
              }
          });
      }
docs: Specify a middleware that will be called for a matching HTTP HEAD
  @param pattern The simple pattern
  @param handler The middleware to call