Add (autogenerated) API documentation?

[leburgel]

TensorKitSectors.jl currently doesn't have any documentation of its own. The only docstrings you can find are the ones manually included in the TensorKit.jl documentation, which is a few clicks away and doesn't (nearly) include everything into its library documentation.

I think it might be appropriate to just add a simple docs page to TensorKitSectors.jl itself which only contains the autodocs of the entire module, but still leave all of the explanations up to the TensorKit.jl documentation like it is right now. That way at least users can find whatever is there to be found without going to a different package and hoping it explicitly mentions what they want to know about.

As an example, I would like to refer to TensorKitTensor.fusiontensor, and adding a reference to the library docs here would be much easier than trying to find the right place in the TensorKit.jl docs to add this.

[leburgel]

While it turns out that there isn't actually a docstring for fusiontensor, I still stand by the above. For one, it would have helped me figure this out a bit sooner :)

[lkdvos]

Definitely in favor of adding docs here. We can gradually start explaining conventions for the individual sectors, but having the infrastructure set up already lowers the bar significantly