nixos/open-webui: fix documentation link formatting

Changed files
+1 -1
nixos
modules
services
+1 -1
nixos/modules/services/misc/open-webui.nix
···
'';
description = ''
Extra environment variables for Open-WebUI.
-
For more details see https://docs.openwebui.com/getting-started/advanced-topics/env-configuration/
+
For more details see <https://docs.openwebui.com/getting-started/advanced-topics/env-configuration/>
'';
};