Publicize new CLI commands

[graygilmore]

WHY are these changes introduced?

Now that all of the commands have been fleshed out with updated UX it's time to start exposing them properly!

WHAT is this pull request doing?

➜  demo-store git:(show-new-commands) h2 --help
Hydrogen commands

USAGE
  $ shopify hydrogen COMMAND

TOPICS
  hydrogen env       List the environments on your linked Hydrogen storefront.
  hydrogen generate  Generates a standard Shopify route.

COMMANDS
  hydrogen build             Builds a Hydrogen storefront for production.
  hydrogen check             Returns diagnostic information about a Hydrogen storefront.
  hydrogen codegen-unstable  Generate types for the Storefront API queries found in your project.
  hydrogen dev               Runs Hydrogen storefront in an Oxygen worker for development.
  hydrogen init              Creates a new Hydrogen storefront.
  hydrogen link              Link a local project to one of your shop's Hydrogen storefronts.
  hydrogen list              Returns a list of Hydrogen storefronts available on a given shop.
  hydrogen preview           Runs a Hydrogen storefront in an Oxygen worker for production.
  hydrogen shortcut          Creates a global `h2` shortcut for the Hydrogen CLI
  hydrogen unlink            Unlink a local project from a Hydrogen storefront.

Checklist

• I've read the Contributing Guidelines
• I've considered possible cross-platform impacts (Mac, Linux, Windows)
• I've added a changeset if this PR contains user-facing or noteworthy changes
• I've added tests to cover my changes
• I've added or updated the documentation

[graygilmore]

@gfscott I wonder if this would be a good time to review all of the descriptions we have for items? I'll be adding content to shopify.dev, too.

[frandiox]

Let's go 🚀

One last question... do you think we need a flag to disable requesting the remote env vars in the dev command? Is there a scenario where someone doesn't want the remote env but needs the storefront to be linked for something else?

Also, perhaps we should get this at the same time: #997

[graygilmore]

Is there a scenario where someone doesn't want the remote env but needs the storefront to be linked for something else?

That's a good question! I think in that case they could unlink and do whatever they needed to do. I don't want to fall into a case of flagitis ahead of time but I think it's something we can keep an eye on for feedback.

[blittle]

🎉