Add Inhomogeneous ER to docs

[ebridge2]

Is your feature request related to a problem? Please describe.

Inability to simulate from IER model.

Describe the solution you'd like

Ability to simulate from IER model.

Provide references (if applicable)

Dos and Don'ts paper.

[bdpedigo]

https://github.com/microsoft/graspologic/blob/005c44d434f7874d9a6e3db35637eba19c72ac7f/graspologic/simulations/simulations.py#L20

I think we just need to add this to docs, currently is semi-private

[bdpedigo]

(could also update the name if necessary)

[bdpedigo]

@ebridge2 trying to clean up old issues - what are your thoughts on this?

[ebridge2]

Looks like a perfect solution to me. Sorry for late reply!