Show SMTP_TLS in config sample (#4477)

.env.production.sample

@@ -69,7 +69,7 @@ SMTP_FROM_ADDRESS=notifications@example.com
 #SMTP_CA_FILE=/etc/ssl/certs/ca-certificates.crt
 #SMTP_OPENSSL_VERIFY_MODE=peer
 #SMTP_ENABLE_STARTTLS_AUTO=true
-
+#SMTP_TLS=true
 
 # Optional user upload path and URL (images, avatars). Default is :rails_root/public/system. If you set this variable, you are responsible for making your HTTP server (eg. nginx) serve these files.
 # PAPERCLIP_ROOT_PATH=/var/lib/mastodon/public-system