schannel: Add TLS 1.3 support

- Support TLS 1.3 as the default max TLS version for Windows Server 2022
  and Windows 11.

- Support specifying TLS 1.3 ciphers via existing option
  CURLOPT_TLS13_CIPHERS (tool: --tls13-ciphers).

Closes curl#8419

docs/CIPHERS.md

@@ -6,7 +6,8 @@ and
 [`--ciphers`](https://curl.se/docs/manpage.html#--ciphers)
 users can control which ciphers to consider when negotiating TLS connections.
 
-TLS 1.3 ciphers are supported since curl 7.61 for OpenSSL 1.1.1+ with options
+TLS 1.3 ciphers are supported since curl 7.61 for OpenSSL 1.1.1+, and since
+curl 7.85 for SChannel with options
 [`CURLOPT_TLS13_CIPHERS`](https://curl.se/libcurl/c/CURLOPT_TLS13_CIPHERS.html)
 and
 [`--tls13-ciphers`](https://curl.se/docs/manpage.html#--tls13-ciphers)
@@ -521,6 +522,16 @@ documentation](https://docs.microsoft.com/en-us/windows/win32/secauthn/tls-ciphe
 Note that the supported ciphers in this case follow the OS version, so if you
 are running an outdated OS you might still be supporting weak ciphers.
 
+### TLS 1.3 cipher suites
+
+(Note these ciphers are set with `CURLOPT_TLS13_CIPHERS` and `--tls13-ciphers`)
+
+`TLS_AES_256_GCM_SHA384`
+`TLS_AES_128_GCM_SHA256`
+`TLS_CHACHA20_POLY1305_SHA256`
+`TLS_AES_128_CCM_8_SHA256`
+`TLS_AES_128_CCM_SHA256`
+
 ## BearSSL
 
 BearSSL ciphers can be specified by either the OpenSSL name (`ECDHE-RSA-AES128-GCM-SHA256`) or the IANA name (`TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256`).

docs/libcurl/opts/CURLOPT_PROXY_TLS13_CIPHERS.3

@@ -58,7 +58,7 @@ CURL *curl = curl_easy_init();
 if(curl) {
   curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
   curl_easy_setopt(curl, CURLOPT_PROXY_TLS13_CIPHERS,
-                   "TLS13-CHACHA20-POLY1305-SHA256");
+                   "TLS_CHACHA20_POLY1305_SHA256");
   ret = curl_easy_perform(curl);
   curl_easy_cleanup(curl);
 }

docs/libcurl/opts/CURLOPT_TLS13_CIPHERS.3

@@ -41,8 +41,8 @@ you will find more details about cipher lists on this URL:
  https://curl.se/docs/ssl-ciphers.html
 
 This option is currently used only when curl is built to use OpenSSL 1.1.1 or
-later. If you are using a different SSL backend you can try setting TLS 1.3
-cipher suites by using the CURLOPT_SSL_CIPHER_LIST option.
+later or SChannel. If you are using a different SSL backend you can try
+setting TLS 1.3 cipher suites by using the CURLOPT_SSL_CIPHER_LIST option.
 
 The application does not have to keep the string around after setting this
 option.
@@ -56,14 +56,15 @@ CURL *curl = curl_easy_init();
 if(curl) {
   curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
   curl_easy_setopt(curl, CURLOPT_TLS13_CIPHERS,
-                   "TLS13-CHACHA20-POLY1305-SHA256");
+                   "TLS_CHACHA20_POLY1305_SHA256");
   ret = curl_easy_perform(curl);
   curl_easy_cleanup(curl);
 }
 .fi
 .SH AVAILABILITY
-Added in 7.61.0.
-Available when built with OpenSSL >= 1.1.1.
+Added in 7.61.0 for OpenSSL. Available when built with OpenSSL >= 1.1.1.
+
+Added in 7.85.0 for SChannel.
 .SH RETURN VALUE
 Returns CURLE_OK if supported, CURLE_NOT_BUILT_IN otherwise.
 .SH "SEE ALSO"