Update documentation. (#880)

### Prerequisites

- [x] This pull request fixes a bug.
- [ ] This pull request adds a feature.
- [ ] This pull request introduces breaking change.

### Description

Updates & adds documentation.

### Issues Resolved

No issue created for this missing documentation.

### Checklist

#### General

- [x] Describe what changes are being made
- [x] Explain why and how the changes were necessary and implemented
respectively
- [ ] Reference issue with `#<ISSUE_NO>` if applicable

#### Resources

- [ ] If you have changed any SCSS code, run `make release` to
regenerate all CSS files

#### Contributors

- [x] Add yourself to `CONTRIBUTORS.md` if you aren't on it already

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Co-authored-by: Luiz F. A. de Prá <luizdepra@users.noreply.github.com>