message: http: update comment about absolute urls
  Updates the comment since absolute URLs can now be handled by the codec
  by setting the allow_absolute_url flag.
diff: @@ -587,10 +587,10 @@ void ConnectionManagerImpl::ActiveStream::decodeHeaders(HeaderMapPtr&& headers,
  }
  // Currently we only support relative paths at the application layer. We expect the codec to have
  - // broken the path into pieces if applicable. NOTE: Currently the HTTP/1.1 codec does not do this
  - // so we only support relative paths in all cases. https://tools.ietf.org/html/rfc7230#section-5.3
  - // We also need to check for the existence of :path because CONNECT does not have a path, and we
  - // don't support that currently.
  + // broken the path into pieces if applicable. NOTE: Currently the HTTP/1.1 codec only does this
  + // when the allow_absolute_url flag is enabled on the HCM.
  + // https://tools.ietf.org/html/rfc7230#section-5.3 We also need to check for the existence of
  + // :path because CONNECT does not have a path, and we don't support that currently.
  if (!request_headers_->Path() || request_headers_->Path()->value().c_str()[0] != '/') {
  connection_manager_.stats_.named_.downstream_rq_non_relative_path_.inc();
  sendLocalReply(Grpc::Common::hasGrpcContentType(*request_headers_), Code::NotFound, "", nullptr,
  