Merge branch...

Merge branch '385241-docs-update-to-add-when-using-alternative-backup-suggestion-of-snapshots-that-this-is-not' into 'master'

Docs clarify Gitaly Cluster and snapshots usage in alternative backup

See merge request !106522



Merged-by: Evan Read <eread@gitlab.com>
Co-authored-by: Alexander Strachan <astrachan@gitlab.com>