robolink.py type-hinting missing for setAsJointTarget and setAsCartesianTarget methods

[sjohnson-FLL]

In robolink.py, the Item class has setAsCartesianTarget and setAsJointTarget methods. In both cases, these methods conclude with return self, which would return an instance of the Item class. While other methods around it have type-hinting for the returned values, this method is not type-hinted for 'Item'.

To fix, either:

1. Add ->'Item' type-hinting to the return values of those methods.
2. Remove return self from those methods. (Breaks backwards-compatibility, but this return behavior was never documented in the first place anyway.)