authentication link in API-only user paragraph is dead (#23628)

Changes not intended to be permanent. Link needs to be fixed.

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Co-authored-by: Rachael Shaw <[email protected]>

Author: nonpunctual

articles/fleetctl.md

@@ -128,7 +128,7 @@ An API-only user does not have access to the Fleet UI. Instead, it's only purpos
 
 ### Create API-only user
 
-Before creating the API-only user, log in to fleetctl as an admin.  See [authentication](https://#authentication) above for details.
+Before creating the API-only user, log in to fleetctl as an admin.  See [authentication](#authentication) above for details.
 
 To create your new API-only user, use `fleetctl user create`: