Update docs to mention "BEGIN SERVERINFO FOR ".

doc/ssl/SSL_CTX_use_serverinfo.pod

@@ -20,14 +20,15 @@ A "serverinfo" extension is returned in response to an empty ClientHello
 Extension.
 
 SSL_CTX_use_serverinfo_file() loads one or more serverinfo extensions from
-a byte array into B<ctx>. The extensions must be concatenated into a 
+a byte array into B<ctx>.  The extensions must be concatenated into a 
 sequence of bytes.  Each extension must consist of a 2-byte Extension Type, 
 a 2-byte length, and then length bytes of extension_data.
 
 SSL_CTX_use_serverinfo_file() loads one or more serverinfo extensions from
-B<file> into B<ctx>. The extensions must be in PEM format.  Each extension
+B<file> into B<ctx>.  The extensions must be in PEM format.  Each extension
 must consist of a 2-byte Extension Type, a 2-byte length, and then length
-bytes of extension_data.
+bytes of extension_data.  Each PEM extension name must begin with the phrase
+"BEGIN SERVERINFO FOR ".
 
 =head1 NOTES