(PUP-2654) Capitalize each segment of a resource type "label"

When a Resource type is stringified it selects the short notation
(e.g. Fee::Foo) over the longer (e.g. Resource[Fee::Foo]), and
when doing so it should output each segment of the FQN with a
capital letter. The current implementation only capitalizes
the initial letter (e.g. Fee::foo::fum).

This fixes the implementation of
TypeCalculator.string_PResourceExpression to capitalize all segments.