Don't show `dataclasses.InitVar` as a class member

Problem Description

Given these definitions which are intended to do very similar things:

from dataclasses import dataclass, field, InitVar


class Dog:
    name: str

    def __init__(self, name: str, id: int):
        self.name = name
        self.vet_code: str = f"{self.name}-{id}"

@dataclass
class Cat:
    name: str
    id: InitVar[int]
    vet_code: str = field(init=False)

    def __post_init__(self, id):
        self.vet_code = f"{self.name}-{id}"

pdoc will produce output like:

class Dog:
    Dog(name: str, id: int)
    name: str
    vet_code: str

@dataclass
class Cat:
    Cat(name: str, id: dataclasses.InitVar[int])
    name: str
    id: dataclasses.InitVar[int]
    vet_code: str

i.e. Cat.id is included as a class member, even though it is type-annotated as an init-only variable.

Proposal

Suppress dataclasses.InitVar class members from output.

Alternatives

We can prefix the InitVar name with _, which will hide it in pdoc output by default...

Additional context

...but it would be nice to not have to do that.

The issue names no implementation files or tests. Reproduce the documented Dog and Cat example in pdoc, then trace how dataclasses members are collected and rendered; done means the InitVar id is absent from Cat's class members while the constructor still shows it and other members remain.