Duplicate page on /index.html of website #1867

Why

When we access to the documentation with index.htmlat the end of the url (https://mithril.network/doc/index.html), the page content is displayed twice. It's not the case with the root url: https://mithril.network/doc/

After investigation, it appears that:

• Docusaurus is not designed to work using index.html in url. Instead, we should use the clean URL.
• This issue is documented on docusaurus repository: fix(core): fix duplicate app render when url accessed through .html extension meta/docusaurus#10059

What

Identify the origin of the problem and attempt to fix it.

How

• Identify the origin of the problem
• Propose a fix if possible