Update docstrings

[wiseodd]

Simplify typehinting

Typehinting in the docstring is redundant.

Before

def f(x: Tensor, n: int = 5) -> Tensor:
    """ Some paragraph.
    
    Parameters
    ----------
    x: Tensor
        Some words.

    n: int, default=5
        Some other words.

After

def f(x: Tensor, n: int = 5) -> Tensor:
    """ Some paragraph.
    
    Parameters
    ----------
    x: Some words.

    n: Some other words. Defaults to `5`.

Add missing docs

There are some of them, e.g. in ParametricLaplace's __init__. Because of this, they're not shown by mkdocstrings.