Documentation book should specify what version it is written for

[grantwwu]

https://cliutils.github.io/CLI11/book/ says at the bottom of the main page that it is based on 1.7, but this is not correct. It actually seems to describe features that, as far as I can tell, haven't made it into the latest stable release, such as the ->expected(Nmin,Nmax) feature for options.

It would also be nice to have the book be versioned, i.e. https://cliutils.github.io/CLI11/1.8/book/.

[henryiii]

That was mostly there since older versions were hosted separately, and as such were not linked to the current version like this one is. That was actually the version of the single file header that was in the docs repository (which is no longer needed since it's in the same repository as the code). It's also partially out of date (the old separately hosted one was not kept up with new changes). I'm hoping that will get fixed by 2.0, so that it will describe a specific version. Until they are in sync, having versions doesn't really make much sense.

Once they are, I'm thinking just adding a "introduced in 2.x" badge would be fine, but we could look into setting up versions as well/instead.

[jzakrzewski]

The "introduced in ..." is better IMHO. It's easier to get an overview of what's available in which version and avoids confusion (like reading new docs when you have older version).