[DOCS] spm intalltion docs show wrong setup for file_roots

[whytewolf]

Description

the docs at https://docs.saltproject.io/en/latest/topics/spm/master.html#update-file-roots show file_roots with numbered lines instead of the list indicator.

file_roots:
  base:
    1. /srv/salt
    2. /srv/spm/salt

Suggested Fix
That should be

file_roots:
  base:
    - /srv/salt
    - /srv/spm/salt

Type of documentation
Salt documentation example

Location or format of documentation
https://docs.saltproject.io/en/latest/topics/spm/master.html#update-file-roots

[ccrvlh]

@whytewolf up for grab? I can help.

[whytewolf]

@lowercase00 yes please. I almost completely forgot about this issue myself.

[ccrvlh]

@whytewolf sure, I'll go through some docs issues to try to fix the easy stuff.

[ccrvlh]

@whytewolf first PR, would be great if you could take a look if the flow was correct: #61979
thanks!

[barbaricyawps]

I think @lowercase00 's PR with this fix was closed because the maintainers asked to remove the changelog fix and didn't. So it was closed because of a lack of a response. I've recreated the fix for this issue.