Improve inline code and code block support in RTL languages

[delucis]

What kind of changes does this PR include?

• Changes to Starlight code

Description

This PR applies a rehype plugin to Starlight Markdown and MDX content to improve appearance in RTL languages.

• Code blocks have dir="ltr" added to the <pre> tag.
• Inline code has dir="auto" added to the <code> tag.
• For code blocks this may be an interim solution until we migrate to Expressive Code.
• Research CodePen while working out the best set-up: https://codepen.io/delucis/pen/vYvBmKx

We don’t currently have an RTL language in our docs site to test with, so I added some Arabic content locally to test these changes.

Before	After

Note that in the second image, the code blocks are left-aligned even though page content is right-aligned and that the inline code reads correctly as @astrojs/* instead of */astrojs@.

[changeset-bot]

🦋 Changeset detected

Latest commit: 10b17f9

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@astrojs/starlight	Patch

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[astrobot-houston]

size-limit report 📦

Path	Size
/index.html	9.58 KB (+0.09% 🔺)
/_astro/*.js	16.33 KB (0%)
/_astro/*.css	8.43 KB (0%)