Add Header Override / Extends Frontmatter Prop

[Bwc9876]

What version of starlight are you using?

0.6.1

What is your idea?

Although auto-generated TOC covers many use cases it can be limiting for people that use custom components, as those headers won't get parsed. So a way to override or perhaps simply extend what headers should be placed in the TOC and their levels, ids, etc should be exposed to the user.

Why is this feature necessary?

This issue would help users who want to utilize Astro components in their starlight projects more.

Do you have examples of this feature in other projects?

• The old Astro docs template had a way to pass headers as an object to its Page component

Participation

• I am willing to submit a pull request for this issue.