Document the difference between `redoc`, `redoc-cli`, and `@redocly/cli` packages

[jasonbarry]

I'm a new user reading the documentation for the first time. I don't understand the relationship between

• redoc
• redoc-cli
• @redocly-cli

Are some of these deprecated? redoc says it can "Generate interactive API documentation from OpenAPI definitions", but so can npx @redocly/cli build-docs. However, I don't see any build-docs command on this page: https://redocly.com/docs/cli/commands/

Which should I use to generate html documentation from openapi spec?