Issue a warning if ambiguous overloads are created using choice types

[brynrhodes]

Allowing the following:

define function Foo(t Integer)
define function Foo(t Choice<Integer, Decimal>)

Results in a potentially ambiguous overload selection and should be discouraged. Add a warning to the translator when this case is detected (i.e. a function with a choice signature is overloaded in a way that one signature completely includes another)

[brynrhodes]

There is a JIRA tracker to the specification to discourage this in the spec and consider deprecating the capability: https://jira.hl7.org/browse/FHIR-44879