Fix typo in max_databases docker config (#895)

Author: erichelgeson

modules/ROOT/pages/docker/ref-settings.adoc

@@ -338,7 +338,7 @@ For more information on the configuration descriptions, valid values, and defaul
 | `+NEO4J_dbms_logs_http_enabled+`
 
 | `dbms.max_databases`
-| `+NEO4J_dbms._max__databases+`
+| `+NEO4J_dbms_max__databases+`
 
 | `dbms.memory.tracking.enable`
 | `+NEO4J_dbms_memory_tracking_enable+`