Refactor shortguides

[nmelehan]

This moves all shortguides that didn't use leaf bundles (e.g. my-shortguide.md) into leaf bundles (e.g. my-shortguide/index.md).

Also changes all shortguide yaml used (i.e. shortguide: true) to use headless instead (i.e. headless: true). headless works a bit different from shortguide: it not only suppresses the guide from the index and the search index, it also prevents the guide from rendering on its own at all (i.e. unless embedded in another guide), so it can't be directly linked to.

Two scripts were used to do this:

1. Convert shortguides to leaf bundles
2. Rename shortguide to headless

This PR also updates the shortguide archetype and the Linode Writer's Guide to show how to use leaf bundles and the headless yaml for shortguides.

A large number of files were changed in this PR. The changes were verified as successful by:

1. Spot-checking that headless guides do not render on their own/are not directly linkable and do not appear in indexes or the search index.
2. Spot-checking that headless guides embed normally.
3. Verifying that the 'Content shortcode is empty' message does not appear when building Hugo locally, which is an error message given by the content shortcode.

[GuessWhoSamFoo]

Why bother with bundles at all if the path is abstracted away?

Hiding from RSS feed should be part of being headless

Limited user note has too much complexity for what can be a shortcode

@Guaris

[nmelehan]

headless won't work on non-bundled guides, and bundles allow us to bundle images in shortguides as we would for any other guide.

We're renaming shortguide to hiddenguide and repurposing it for some other guides that we do want to render and be directly linkable.

I thought that headless by itself should hide a guide from RSS, but I'll check on that.

I prefer having another shortguide to having another shortcode (for limited user note), but maybe other members of the team disagree

[nmelehan]

Hi @GuessWhoSamFoo

Here's what I've found about why headless should suppress a guide from the RSS feed without needing show_on_rss_feed also set to false:

• headless prevents a guide from ending up in .Site.RegularPages

• We use .Data.Pages to compile the RSS feed (here)

• .Pages is an alias of .Data.Pages

• In the home context, .Pages is the same as .Site.RegularPages

• We only render RSS in the home context

Can I ask if you've seen any shortguides in the RSS feed since this PR? I haven't seen any myself