Broken Github-link when trying to edit Documentation #12197

Describe the bug
Hi!
I'm trying to learn how to develop blocks with Gutenberg. I'm using the Developer handbook:
https://wordpress.org/gutenberg/handbook/readme/. I sometimes come across stuff I can update the documentation with that I think would help others in the same position as me.

The handbook seems to be able to give us that opportunity since there is a Link to the github repo with the title "Edit". However when following that link i got a 404.

To Reproduce
Steps to reproduce the behavior:

1. Go to https://wordpress.org/gutenberg/handbook/blocks/introducing-attributes-and-editable-fields/
2. Click on 'Edit' just below 'Introducing attributes and Editable fields'
3. I get redirected to the 404 page of github.

Expected behavior
I would like to be able to edit the page and send a pull request.

Screenshots