doc: do not reference SSL when discussing SNI

Co-authored-by: Rich Trott <[email protected]>

Author: tniessen

doc/api/tls.md

@@ -118,7 +118,7 @@ SNI (Server Name Indication) are TLS handshake extensions:
 
 * ALPN: Allows the use of one TLS server for multiple protocols (HTTP, HTTP/2)
 * SNI: Allows the use of one TLS server for multiple hostnames with different
-  SSL certificates.
+  certificates.
 
 ### Pre-shared keys