feat: add empty slot fallback content info (#8302)

[jdtjenkins]

Description (required)

This PR adds an example of how passing empty slots causes that slot's default content to not render.

Related issues & labels (optional)

• Closes #8302

For a new/changed feature in an upcoming Astro release?

No

First-time contributor to Astro Docs?

Yes :3

Discord: Jumper#8174

[vercel[bot]]

The latest updates on your projects. Learn more about Vercel for Git ↗︎

Name	Status	Preview	Updated (UTC)
docs	✅ Ready (Inspect)	Visit Preview	Jun 5, 2024 4:27pm

[astrobot-houston]

Hello! Thank you for opening your first PR to Astro’s Docs! 🎉

Here’s what will happen next:

1. Our GitHub bots will run to check your changes. If they spot any broken links you will see some error messages on this PR. Don’t hesitate to ask any questions if you’re not sure what these mean!

2. In a few minutes, you’ll be able to see a preview of your changes on Vercel 🥳

3. One or more of our maintainers will take a look and may ask you to make changes. We try to be responsive, but don’t worry if this takes a few days.

[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

Locale	File	Note
en	basics/astro-components.mdx	Source changed, localizations will be marked as outdated.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.