Self-loops are not rendering

[Zi-Gao]

Edges where the source and target are the same node are not visible on the canvas.

[anAcc22]

Thanks for opening this issue! I'm a little busy at the moment so I won't work on this task in the immediate future. Self loops are also a bit tricky and will likely need quite a few refactors since all the edge rendering mechanisms never take self-loops into account... But I do think it's a good feature suggestion and I'll work on it another day!