fix docs: typo in DATABASE_SSL_SNI description

Author: dashitongzhi

website/docs/configuration/environment_variables.md

@@ -19,7 +19,7 @@ TeslaMate accepts the following environment variables for runtime configuration:
 | **DATABASE_TIMEOUT**                   | The time in milliseconds to wait for database query calls to finish                                                                                                                                                                                                                                              | 60000                                                                                                                                                               |
 | **DATABASE_SSL**                       | Set to `true` if SSL should be enabled or `noverify` if certificate verification should not be performed.                                                                                                                                                                                                        | false                                                                                                                                                               |
 | **DATABASE_SSL_CA_CERT_FILE**          | Path to a file containing PEM-encoded CA certificates (required if `DATABASE_SSL` is set to `true`)                                                                                                                                                                                                              |                                                                                                                                                                     |
-| **DATABASE_SSL_SNI**                   | set SNI for host undel ssl mode                                                                                                                                                                                                                                                                                  |                                                                                                                                                                     |
+| **DATABASE_SSL_SNI**                   | set SNI for host under SSL mode                                                                                                                                                                                                                                                                                  |                                                                                                                                                                     |
 | **DATABASE_IPV6**                      | Set to `true` if IPv6 should be used                                                                                                                                                                                                                                                                             | false                                                                                                                                                               |
 | **VIRTUAL_HOST**                       | Host part used for generating URLs throughout the app                                                                                                                                                                                                                                                            | localhost                                                                                                                                                           |
 | **URL_PATH**                           | Path used for generating URLs (can be used with a reverse proxy)                                                                                                                                                                                                                                                 | /                                                                                                                                                                   |