[joss] Most operations fail on empty hypergraph

[szhorvat]

Describe the bug

Most operations fail on empty hypergraph.

To Reproduce

hh = hnx.Hypergraph()
hn.draw(hh) # errors
hh.is_connected() # errors
hh.bipartite() # errors

Almost all functions / methods I tried threw a non-intuitive error.

HNX 2.1.3

Ref openjournals/joss-reviews#6016

[bonicim]

v2.3.2 addresses the non-intuitive errors for hnx.draw() and Hypergraph.bipartite()`.

On an empty hypergraph, hnx.draw() will draw a blank graph. No error is raised; Hypergraph.bipartite() will return an empty networkx graph.

hh.is_connected() will be addressed in a future patch release.