Documentation: fix unexisting path sshd_config.phabricator.example

Summary:
Since the example file was renamed, this change makes the documentation consistent with it.

Also we added exactly one-space somewhere, to create a super-satisfying indentation an example block. You're welcome.

Ref T15006

Test Plan: Check that the documentation is at least 0.000001% better now.

Reviewers: O1 Blessed Committers, avivey

Reviewed By: O1 Blessed Committers, avivey

Subscribers: tobiaswiese, Matthew, Cigaryno

Maniphest Tasks: T15006

Differential Revision: https://we.phorge.it/D25410