Introduce docs versioning of some sort

[ItamarShDev]

Case study

I have started to work on a small playground project by mimicking my Next.js based blog with Remix.run too.
This helps me better understand the library.

At the time of starting , the Remix amazing docs had a guide on creating a blog with .md files, which was exactly what i have needed!

I have started to work on it on some nights and then have contracted COVID-19 and left the computer for a week.

When i was well enough to come back, i have noticed that the blog guide is different.
I was able to find the original one in the repo easily here, and continue working.

This gave me an idea:

Allow users to see old versions of the docs

How

I have compiled 3 ideas, but more may be available

1. Route as source of truth

Use the url to allow to go back to old versions.
Either by using the v1 in the url, or with any other url params.

2. Archive

Add Archive section that has at least the last major change.

3. Keep old versions

In the side bar, allow listing different versions

instead of

[gerbyzation]

The pain of this is quite noticable with nextjs for example, they are changing more APIs and the website only has the latest version available so if you're still on v12/13 you might have to dive into source to find documention. It would be really good if you could switch to previous major versions of the documentation

[sergiodxa]

The docs already support versioning, but the version picker only list the last one of each major, however you can change the URL to get any version, eg this is v1.1.1 docs https://remix.run/docs/en/v1.1.1.

[gerbyzation]

Right, I completely glanced over that as a version selector, as it says "main" while I was looking for a version indicator 😄