QUIC: removed cancelable flag from QUIC and HTTP/3 events. All these events are created in context of a client connection and are deleted when the connection is closed. Setting ev->cancelable could trigger premature connection closure and a socket leak alert.

# Copyright (C) Igor Sysoev
# Copyright (C) Nginx, Inc.


cat << END >> $NGX_AUTO_CONFIG_H

#ifndef $have
#define $have  $value
#endif

END