A previous change in 3.0 moved our auth backend support to use the new

entrypoint-based registry classes, deprecating the old methods. This

resulted in a breakage where auth backends couldn't be found, due to a

typo in the entrypoint name.
This change fixes that typo, and also fixes the deprecation warnings and

documentation to both reference the correct objects/functions by path and

to add missing spaces.

Verified that the auth backends could load again.