Corrected configuration file reference (#2664)

Corrected a copy-paste error from active_directory_authentication.md, which reference sssd.conf. Here it should be smb.conf.

Author: GMouzourou

docs/guides/security/authentication/active_directory_authentication_with_samba.md

@@ -142,7 +142,7 @@ If this succeeds, you have successfully configured Linux to use Active Directory
 
 In a completely default setup, you will need to log in with your AD account by specifying the domain in your username (e.g., `[email protected]`). If this is not the desired behavior and you instead want to be able to omit the default domain name at authentication time you can configure Samba to default to a specific domain.
 
-This is a relatively straightforward process, requiring a configuration tweak in your SSSD configuration file.
+This is a relatively straightforward process, requiring a configuration tweak in your `smb.conf` configuration file.
 
 ```sh
 [user@host ~]$ sudo vi /etc/samba/smb.conf