Explain difference between ssl:// and tls:// for default_host (#7099)

config/config.inc.php.sample

@@ -30,7 +30,8 @@ $config['db_dsnw'] = 'mysql://roundcube:pass@localhost/roundcubemail';
 // The IMAP host chosen to perform the log-in.
 // Leave blank to show a textbox at login, give a list of hosts
 // to display a pulldown menu or set one host as string.
-// To use SSL/TLS connection, enter hostname with prefix ssl:// or tls://
+// Enter hostname with prefix ssl:// to use Implicit TLS, or use
+// prefix tls:// to use STARTTLS.
 // Supported replacement variables:
 // %n - hostname ($_SERVER['SERVER_NAME'])
 // %t - hostname without the first part

config/defaults.inc.php

@@ -134,7 +134,8 @@ $config['redis_debug'] = false;
 // The IMAP host chosen to perform the log-in.
 // Leave blank to show a textbox at login, give a list of hosts
 // to display a pulldown menu or set one host as string.
-// To use SSL/TLS connection, enter hostname with prefix ssl:// or tls://
+// Enter hostname with prefix ssl:// to use Implicit TLS, or use
+// prefix tls:// to use STARTTLS.
 // Supported replacement variables:
 // %n - hostname ($_SERVER['SERVER_NAME'])
 // %t - hostname without the first part