Broken links in dotty.epfl.ch

[nicolasstucki]

Links in Table of Contents of https://dotty.epfl.ch/ are broken.

• https://dotty.epfl.ch/_docs/docs/reference/index.html
• https://dotty.epfl.ch/_docs/docs/contributing/index.html
• https://dotty.epfl.ch/_docs/docs/internals/index.html
• https://dotty.epfl.ch/_docs/blog/index.html