Add additional phpredis configs

Mention the newly added phpredis config options that users are able to specify (see: laravel/framework#54191)

redis.md

@@ -176,7 +176,7 @@ By default, Laravel will use the PhpRedis extension to communicate with Redis. T
         // ...
     ],
 
-In addition to the default configuration options, PhpRedis supports the following additional connection parameters: `name`, `persistent`, `persistent_id`, `prefix`, `read_timeout`, `retry_interval`, `timeout`, and `context`. You may add any of these options to your Redis server configuration in the `config/database.php` configuration file:
+In addition to the default configuration options, PhpRedis supports the following additional connection parameters: `name`, `persistent`, `persistent_id`, `prefix`, `read_timeout`, `retry_interval`, `max_retries`, `backoff_algorithm`, `backoff_base`, `backoff_cap`, `timeout`, and `context`. You may add any of these options to your Redis server configuration in the `config/database.php` configuration file:
 
     'default' => [
         'url' => env('REDIS_URL'),