Fixed SSL mode in docs (#467)

Author: albertcansado

docs/content/docs/5.customizing-the-image/4.configuring-ssl.md

@@ -9,7 +9,7 @@ SSL is disabled by default but can be turned on by setting `SSL_MODE`:
 
 - `off` (default): HTTP only.
 - `mixed`: HTTP and HTTPS.
-- `on`: HTTPS only. HTTP requests will be redirected to HTTPS.
+- `full`: HTTPS only. HTTP requests will be redirected to HTTPS.
 
 ## Self-signed Certificate Example
 If you set `SSL_MODE` to `mixed` or `full`, a self-signed certificate will be generated by default.
@@ -98,4 +98,4 @@ If you're using NGINX Unit, you also have the option of setting `UNIT_CERTIFICAT
 ## Using Let's Encrypt
 If you'd like to use Let's Encrypt (what we use), it's best to use a reverse proxy like [Traefik](https://traefik.io/traefik/) or [Caddy](https://caddyserver.com/).
 
-Providing examples for those are out of the scope of this project, but we may consider adding examples in other projects in the future.
+Providing examples for those are out of the scope of this project, but we may consider adding examples in other projects in the future.