I use this extension too for general markdown, but it is not generally helpful for complex editing the V1 docs because the formatting of the content is not the same as the rendered site.
For simple fixes, the edit link on the page itself is the easiest to way to correct typos and make small changes. The issue with that one is that you don’t get a good formatted preview there either.
If you want to be able to see the formatting exactly, the only way to get it exactly as published on the site, is to follow the instructions here and run it locally.
I’ve done quite a lot of editing on the V1 docs and it’s really nice editing it locally and watching the site update live to verify your formatting, etc.
I also published this PR for anyone who knows how to do it to be able to spin up a Docker container running the mkdocs system to edit the docs without affecting your local system (I meant to go back and add instructions to run it… but haven’t got to it…)