HTTP/3: implement keepalive for hq. Previously, keepalive timer was deleted in ngx_http_v3_wait_request_handler() and set in request cleanup handler. This worked for HTTP/3 connections, but not for hq connections. Now keepalive timer is deleted in ngx_http_v3_init_request_stream() and set in connection cleanup handler, which works both for HTTP/3 and hq.

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


cat << END >> $NGX_AUTO_HEADERS_H

#ifndef $have
#define $have  1
#endif

END