use the bracketed syntax; avoid name resolution for all literal
addresses.

* src/ne_session.h: Clarify host parameter must match RFC 3986 syntax.

* src/ne_private.h (struct host_info): Add literal field.

* src/ne_session.c (free_hostinfo): Free literal field.
  (set_hostinfo): Parse and store IP literals including bracketed
  IPv6-literal.
  (ne_session_create) Use literal field to determine TLS SNI mode.

* test/utils.c (session_server): Use bracketed IPv6 literals.

* test/request.c (ipv6_host_checker, serve_v6_check, ipv6_literal):
  Test for bracketed form of IPv6 literals.

* src/ne_request.c (do_connect): Update comment.

* test/utils.c (session_server): Store the hostname.
  (get_session_host): New function.

* test/request.c (status, status_chunked): Use get_session_host() to
  accurately create the expected status notifier output.

matching a DNS name against an IP address, and remove URI altname
support since this is not specified by RFC 9110/6125.

* src/ne_openssl.c (check_identity): Take the host_info rather than a
  URI; only test DNS names for a non-literal identifier, and only test
  IP addresses for a literal identifier.
  (check_certificate): Adjust accordingly.

* src/ne_gnutls.c (check_identity, check_certificate): Update
  similarly.

* src/ne_session.c (ne__ssl_match_hostname): Drop now unnecessary
  safety check for IP addresses here.

* test/ssl.c (uri_altname, fail_bad_urialtname): Removed tests.
  (fail_ssl_request_with_error2): Update to use
  fakeproxied_session_server.
  (cert_identities): Drop altname8.cert (URI altname).

* test/makekeys.sh, test/openssl.conf: Drop URI altname cert generation.