There probably isn't, feel free to update the on-wiki documentation.
The basic answer is that instead of doing
$wgAuth = new LdapAuthenticationPlugin();
you instead configure AuthManager to use LdapPrimaryAuthenticationProvider with something like this
$wgAuthManagerAutoConfig['primaryauth'] += [ LdapPrimaryAuthenticationProvider::class => [ 'class' => LdapPrimaryAuthenticationProvider::class, 'args' => [ [ 'authoritative' => true, // don't allow local non-LDAP accounts ] ], 'sort' => 50, // must be smaller than local pw provider ], ];
Or, if you're already setting $wgAuthManagerConfig in your configuration, include that bit in the appropriate place there.
Beyond that I can't really help you, the LdapAuthentication extension is badly in need of a redesign and rewrite from someone who understands the stuff it's currently trying to do.