Docs outdated

[PeterJCLaw]

The published docs at https://asttokens.readthedocs.io/en/latest/index.html appear to be somewhat outdated, having been built against c8697dc.
I'm not sure exactly what's changed in the API since then, however it would be great if they could reflect the current version.

[dsagal]

The published docs have been updated!

Not sure why readthedocs wasn't building automatically for.... quite a while...

[alexmojaki]

Since stable and latest differ, I think the badge in the README should link to stable

[alexmojaki]

^ point above needs reiterating, even though they match at the moment.

Anyway, the docs are still not building automatically. I just rebuilt stable and latest. They've been updated, but they don't mention the new ASTText.