[V6]: Various fixes in content collections pages

[ArmandPhilippot]

Description (required)

While reviewing #12604 I figured a PR to that branch would be easier than adding review comments so here's what I suggest to update. This PR mostly fixes code snippets, following HiDeoo's feedback, and rewords a section in the "Content Loader" reference to mention live loaders.

Here's the details:

• astro:content:

  • Adds empty lines after code snippets (just a readability nit while checking the file)
  • Adds a missing title on a code snippet
  • Fixes the SchemaContext code snippet by adding a loader, and adds highlighting to bring attention on the right parts
  • nit: Replaces backticks with quotes around Content Collection because this is not code?

• Content Loader reference:

  • Updates "What is a loader?" to talk about live loaders as well (not quite sure about the wording, but the idea is there)
  • Swaps a link in "What is a loader?": if people are on this page maybe they expect to be redirected to the right section on this page, then from there they be can redirected to the guide if needed.
  • Updates the code snippets to make them valid (remove schema, add missing imports)
  • nit: Replaces backticks with quotes around Content Collection because this is not code?

• Content Collections guide:

  • Removes unnecessary imports from some code snippets
  • Adds necessary imports in some code snippets
  • Adds some missing code snippets title, mostly to code snippets using Astro.params
  • Updates the file() loader snippet to improve the parser visibility and prevent unnecessary overflow on large screens (we don't highlight the curly braces anymore though)
  • In "Cache hints", I replaced the "fetch data" comment with a fictive function to make the code "valid" and we had an issue with lastModified (the first one): item doesn't exist so I came up with a pseudo code that seems to do what the comment describes
  • It seems LiveCollectionValidationError and LiveEntryNotFoundError are not exported from astro:content but from astro/content/runtime, but looking at the most recent update in the roadmap proposal this should be available from astro/loaders?

Also noting that I did not fix a Typescript error we have in multiple places because of the default preset. For example, Astro.params.slug can be undefined so when we use it directly in a function we get:

Argument of type 'string | undefined' is not assignable to parameter of type 'string'.
  Type 'undefined' is not assignable to type 'string'.ts(2345)

Related issues & labels (optional)

• Related: to be merged in [v6] New content collections guide includes live collections #12604
• Suggested label: 6.0, code snippet update, improve or update documentation

[astrobot-houston]

Lunaria Status Overview

🌕 This pull request will trigger status changes.

Learn more

By default, every PR changing files present in the Lunaria configuration's files property will be considered and trigger status changes accordingly.

You can change this by adding one of the keywords present in the ignoreKeywords property in your Lunaria configuration file in the PR's title (ignoring all files) or by including a tracker directive in the merged commit's description.

Tracked Files

File	Note
en/guides/content-collections.mdx	Source changed, localizations will be marked as outdated.
en/reference/content-loader-reference.mdx	Source changed, localizations will be marked as outdated.
en/reference/modules/astro-content.mdx	Source changed, localizations will be marked as outdated.

Warnings reference

Icon	Description
🔄️	The source for this localization has been updated since the creation of this pull request, make sure all changes in the source have been applied.

[sarah11918]

These changes look great, @ArmandPhilippot ! We've been focusing a lot on updating the content collections guide material, but yes, there is still some more generic text in here that needs updating. And, updating the code snippets to all be functional is great!

Left some thoughts re: what we could maybe do in astro-content. See what you think!

[yanthomasdev]

Thank you! The backticks in text were bothering me deeply while reviewing this file in the other PR