Scaladoc: Fix rendering dependent function types

[Sporarum]

A valid dependent function type, such as:
type J = (a: A) => a.type
is reported as:
type J = A => A { def apply(a: A): a; }

[pikinier20]

Thank you for reporting this issue!
There were actually two or three things that overlapped:

1. We didn't handle dependent function type desugaring
2. We rendered TermParamRef's without .type suffix
3. We check if applied type is a function and render it as A => B instead of Function1[A, B] which made this example look weird as if the return type had refinement.

Let's wait for the CI to pass. Locally, the example looks good:

@KacperFKorban Could you take a look at it?

[KacperFKorban]

Will the following type be handled correctly?

type F = [A] => (a: A) => a.type

[pikinier20]

type F = [A] => (a: A) => a.type

It works. Just in case I added the testcase to the tests.