`view-markdown-source` is not being loaded on `*.md` pages #2619

When I load https://github.com/fastify/fastify/blob/master/docs/Getting-Started.md with view-markdown-source and "Show the features enabled on each page in the console" enabled, I can see that the option is not loaded. This is happening on any markdown document in that repository, as well as on other repositories.

Extension version: 19.11.30