docs(admin): Update examples in setup

[Inhishonor]

☑️ Resolves

• The documentation had incorrect file names in the examples, which is frustrating for users using the docs.

[rakekniven]

Hello @Inhishonor ,

while browsing https://download.nextcloud.com/server/releases/ I saw that there are no files named e. g. "latest.tar.bz" but "nextcloud-x.y.z.tar.bz".
I therefore consider the current documentation to be correct.

which is frustrating for users using the doc

How do you come to this assumption?
We haven't had any complaints on our forums IIRC.

[rakekniven]

Will close it due to inactivity.
Feel free to re-open by adding context.