Detect cyclical class hierarchy and prevent infinite recursion when calculating all fields and methods of an object

[datho7561]

Let's say we have the following classes:

• ClassA which extends ClassC
• ClassB which extends ClassA
• ClassC which extends ClassB

JDT reports an error for this since it can't be compiled. If you make a Qute template that includes one of these classes as a parameter, then open up completion:

{@org.acme.ClassA objectA}
{objectA.|}

Then you won't ever get completion back, since qute-ls uses recursion in order to collect the fields and methods of the subtypes, and will be stuck cycling between the 3 types. I'd be nice to prevent the infinite recursion in this case.