Add support for astro framework

[jorgebef]

With the increase in popularity of Astro, I have been trying to use it but support was not there. Added with this simple PR.

For reference: Astro.build site

[hankandre]

@jorgebef thank you for doing this! I was just adding astro to my autotag filetypes when I saw your PR.

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[MB-Izzo]

Is this going to be merged? It would be very useful