documentation updates

- [ ] update our credentials documentation about the `source:name` structure of creds
- [ ] convert the `AWS.configuration.description.awssam.debug.credentials` message in package.json to a markdownDescription and providing a link to the docs via hyperlink in the localized string. https://github.com/aws/aws-toolkit-vscode/pull/1725#discussion_r655686537
- [ ] “downloadLambda” https://github.com/aws/aws-toolkit-vscode/pull/1826
- [ ] S3: "Upload to S3" https://github.com/aws/aws-toolkit-vscode/pull/1799
- [ ] S3: "Open in editor" #2349
- [ ] Credentials can be sourced from environment or EC2 metadata service, don't need `~/.aws/` https://github.com/aws/aws-toolkit-vscode/pull/1833
> - EC2 instance metadata and environment variable credential providers are automatically used if appropriate.
> - Environment variables source: Available if the AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY environment variables have been set. Optionally will accept a default region from `AWS_REGION` and a session token from AWS_SESSION_TOKEN.
> - `credential_source`: Support for `credential_source` ([docs](https://docs.aws.amazon.com/sdkref/latest/guide/setting-global-credential_source.html)) in a credential profile. This supports EC2 instance, ECS cluster, and environment variable based sources. A `role_arn` may also be provided.
- **Note:** instance credentials (`ec2:instance`) [require a role to be attached](https://www.github.com/aws/aws-toolkit-vscode/issues/1854) to the EC2 instance
- [x] Update AWS Cloud9 documentation with CloudWatch Logs functionality: https://github.com/aws/aws-toolkit-vscode/pull/1832
- Gloss over limitations provided within (don't mention save command, non-readonly editor, etc)
- [x] typescript
- [x] update docs to reflect rename of "Connect to AWS" => "Choose AWS Profile" #2351
- [ ] CFN/cloudformation yaml support
- requires RedHat YAML extension
- implicitly activated for `template.yaml` files.
- does _not_ appear in the languages menu
- [ ] SAM typescript debug:
- requires a `*.ts` or `tsconfig.json` file in the top level of the Lambda app dir. #2086
- "What was the reason again for using a minimal tsconfig rather than the user's configuration file?"
- users will quickly run into problems if they start to deviate from the generated config:
```
target: 'es6',
module: 'commonjs',
typeRoots: ['node_modules/@types'],
types: ['node'],
```
- this config is very bare and will break for a lot of use-cases (synthetic imports, path mappings, base URL, esModuleInterop)
- [ ] `target=template,api` no longer supports `memoryMb`, `timeoutSec` https://github.com/aws/aws-toolkit-vscode/pull/2061
- [ ] `AWS: Show or Hide Regions` command #2569
- [ ] sam run/debug now uses the Toolkit active credentials #2573
- [ ] SSO auth features:
- Toolkit detects any profile with a `start_url` as being an sso provider.
- Toolkit prompts the user for any missing profile parameters when they login to an sso profile.
- [ ] ECS interactive terminal https://github.com/aws/aws-toolkit-vscode/pull/2905
- [ ] CFN/SAM template scanning is driven by vscode settings `files.exclude`, `search.exclude`, and `files.watcherExclude`.
- [ ] add faq/troubleshooting item for corrupted vscode state: https://github.com/aws/aws-toolkit-vscode/issues/4102

## Backlogged

These items have backlog items are tracked in the doc writer backlog:

- [ ] template.yaml schema override: #3012#issuecomment-1379430118
- [ ] https://github.com/aws/aws-toolkit-vscode/pull/1835
- [ ] codelenses: mention Toggle command at the top of the codelens section of docs and quickstart
- [ ] codelenses are now disabled by default: https://github.com/aws/aws-toolkit-vscode/pull/2746

Start by reviewing the unchecked checklist items, the linked pull requests and issues, and the relevant entries in package.json. Separate the remaining documentation topics into focused changes, then update the appropriate AWS Toolkit for VS Code docs. Done means each selected item is documented accurately and its related checklist entry can be marked complete.

Written by the indexing model from the issue text.