Cleanup documentation

[lizliz]

Keeping a list for myself of minor documentation updates I've found while working on the paper.

[lizliz]

Title should just be ECT since it's no longer specific to graphs: https://munchlab.github.io/ect/ect_on_graphs.html#ect.ect.ECT

Also needs some intro "basic use code" stuff in the front of the documentation

[lizliz]

Add ECTResult class to autodocumentation