Website/Docs: debian install - run apt update first

Apologies for not creating an issue first but it seemed like a simple docs change. 

`apt install terraform` requires the  `apt update` before terraform can be installed.

Docs: Add newer Debian & Ubuntu versions to repo list

Improve `.terraformignore` doc formatting

Fix example for values-representation in docs for JSON Format internals

update hcl@v2.11.1

Cloud: Do not ask to migrate empty default workspace

When migrating from an explicit local backend to Terraform Cloud, we ask
if you want to migrate the state. If there is no state to migrate we
should not ask if they want to migrate the emptiness.

Cloud: Apply without init error message

When going from a local backend to Terraform Cloud, if you skip the
`terraform init` and run `terraform apply` this will give the user more
clear instructions.

When terraform detects that a user has no workspaces that map to their current configuration, it will prompt the user to create a new workspace and enter a value name. If the user ignores the prompt and exits it, the legacy backend (terraform.tfstate) will be left in a awkward state:

1. This saved backend config will show a diff for the JSON attributes "serial", "tags" and "hash"
2. "Terraform workspace list" will show an empty list
3. "Terraform apply" will run successfully using the previous workspace, from the previous config, not the one from the current saved backend config
4. The cloud config is not reflective of the current working directory

Solution: If the user exits the prompt, the saved backend config should not be updated because they did not select a new workspace. They are back at the beginning where they are force to re run the init cmd again before proceeding with new changes.

update hcl@v2.11.0

Previously we ended up losing all of the error message detail produced by
the registry address parser, because we treated any registry address
failure as cause to parse the address as a go-getter-style remote address
instead.

That led to terrible feedback in the situation where the user _was_
trying to write a module address but it was invalid in some way.

Although we can't really tighten this up in the default case due to our
compatibility promises, it's never been valid to use the "version"
argument with anything other than a registry address and so as a
compromise here we'll use the presence of "version" as a heuristic for
user intent to parse the source address as a registry address, and thus
we can return a registry-address-specific error message in that case and
thus give more direct feedback about what was wrong.

This unfortunately won't help someone trying to install from the registry
_without_ a version constraint, but I didn't want to let perfect be the
enemy of the good here, particularly since we recommend using version
constraints with registry modules anyway; indeed, that's one of the main
benefits of using a registry rather than a remote source directly.

backend/http: supply logging.LogOutput() to retryable client

configs: Add sensitive marks for nested attributes

core: Fix schema loading for deleted resources

The HashiCorp APT server supports several distro releases that were not in this list,
leading to a false impression that they aren't supported.

Note, Ubuntu has a new release twice a year, so periodic maintenance
is needed here.

command/init: Add -cloud alias to -backend, adjust `init` help output

The `root_module.resources[].sensitive_values` key in the example output was incorrectly named and clashed with the regular `root_module.resources[].values` key.

Object values returned from providers have their attributes marked as
sensitive based on the provider schema. This was not fully implemented
for nested attribute types, which is corrected in this commit.

This helps to distinguish what is a `/` (as a directory separator)
from a "/" (as in "his/her").

Resource instances removed from the configuration would previously use
the implied provider address. This is correct for default providers, but
incorrect for those from other namespaces or hosts. The fix here is to
use the stored provider config if it is present.

Cloud integration requires input for migrations

We cannot programmatically migrate workspaces to Terraform Cloud without
prompts, so `-input=false` should not be allowed in those cases.

There are 4 scenarios where we need input from a user to complete
migrating workspaces to Terraform Cloud.

1.) Migrate from a single local workspace to Terraform Cloud

* Terraform config for a local backend. Implicit local (no backend
  specified) is fine.
* `terraform init` and `terraform apply`
* Change the Terraform config to use the cloud block
* `terraform init -input=false`
* You should now see an error message

2.) Migrate from a remote backend with a prefix to Terraform Cloud with
  tags

* Create a workspace in Terraform Cloud manually. The name should
  include a prefix, like "app-one"
* Have the terraform config use `backend "remote"` with a prefix set to
  "app-"
* `terraform init` and `terraform apply`
* Update the Terraform config to use a cloud block with `tags
  = ["app"]`. There should not be a prefix defined in the config now.
* `terraform init -input=false`
* You should now see an error message

3.) Migrate from multiple local workspaces to a single Terraform Cloud
  workspace
* Create one or many local workspaces
* `terraform init` and `terraform apply` in each
* Change the Terraform config to use the cloud block
* `terraform init -input=false`
* You should now see an error message

4.) Migrate to Terraform Cloud and ask for a workspace name
* Create several local workspaces
* `terraform init` and `terraform apply` in each
* Change the Terraform config to use the cloud block with tags
* `terraform init -input=false`
* You should now see an error message

Revert "migrate docs to mdx"

This reverts commit 3cb12b5a.

Create a function for logic that assigns value to initReason var after changing backend configuration (#29967)

* Create a function for logic that assigns value to initReason var after changing backend configuration

Create func determineInitReason() for logic block that assigns value to initReason var after changing backend/cloud configuration block or migrating to a different type of backend configuration. Also clarify 'cloud' configuration block message to say 'Terraform Cloud configuration block has changed' instead of 'Terraform Cloud configuration has changed'.

cli: Fix nested single and map diff rendering

Indentation was out by two spaces. This is now consistent with the other
displays of object/map values: four spaces for each nesting level.

Some of the wording here needed adjusting with the change that backends
largely reflect state snapshot storage (removing 'enhanced'
designation), and that a 'backend' is not necessarily always present.

This fixes an issue where a user could not disable initialization of the
'cloud' configuration block (As is possible with -backend=false), as
well as add some syntactic sugar around -backend by adding a mutually
exclusive -cloud alias.

cli: Fix diff for nested set unchanged elements

Unchanged elements in nested attributes backed by sets were previously
misrendered as empty objects. This commit removes the additional
brackets and adds a count of unchanged elements.

Fix failing checks