Determines the angle that loops extend from the node in cases when the source and
target node of an edge is the same. The angle is specified from the 12 o’clock
position and it progresses clockwise for increasing positive values.
The default is -45deg (extending to the upper left).
Determines the angle between the leaving and returning edges in loops. Positive
values result in clockwise looping and negative values result in counter-clockwise
looping. Default is -90deg.
Loop edges For loops (i.e. same source and target)
https://js.cytoscape.org/#style/loop-edges