Promotes the given method definition to an instance of
MethodWithNext, thereby recording the next
method in the nextMethod slot.
.methodWithNext(method, nextMethod, .cache = FALSE)the MethodDefinition object to promote
the MethodDefinition object to record as the next method
whether to cache the promoted method definition object
(using methods::cacheMethod())
an instance of MethodWithNext,
which has the next method in the nextMethod slot