Improve doc strings and add type annotations

[Bronzila]

Improve docstrings of DEHB to fit the Google Style Guide for python comments. When adjusting the doc strings it would make sense to adjust the signatures to add type annotations. These changes would improve the general readability of the code.

[Neeratyoy]

Can we link this issue to the docs or stylecheck related issues/PRs?

[eddiebergman]

A note on mkdocstrings[python] and using google-style. As long as your function arguments use types, then I've opted to not put them in the docstrings. It makes the docstrings more concise and less likely there's a mismatch. mkdocstring will automatically pull the type definitions from the declaration.

Also ruff has linter checks for missing or extra parameters :) However this check only triggers if there's an Args: entry in the docstring.