As explained in the changes: The 'enhanced' backend terminology, which
only truly pertains to the 'remote' backend with a single API (Terraform
Cloud/Enterprise's), has been found to be a confusing vestige which need
only be explained in the context of the 'remote' backend.
These changes reorient the explanation(s) of backends to pertain more
directly to their primary purpose, which is storage of state snapshots
(and not implementing operations).
That Terraform operations are still _implemented_ by the literal
`Backend` and `Enhanced` interfaces is inconsequential a user of
Terraform, an internal detail.
During the language/CLI docs reorg, we noticed several pages that were no longer
viable; some were redundant, some useless, and some just very obsolete.
Since we were trying to avoid breaking links at the time, we opted to remove
them from the navs and leave them as "ghost pages" — still accessible, but not
findable.
This commit finally cleans these ghosts up and updates any remaining links to
relevant modern pages. Bustin' makes me feel good. 👻🚫
Chris Arcand