Render google-style docstrings to markdown

[Gankra]

Currently we punt on this and just wrap the raw contents in a plaintext codeblock:
https://github.com/astral-sh/ruff/blob/6de84ed56eac4f1f3efe9d8a9d47c9b30a445707/crates/ty_ide/src/docstring.rs#L65-L73

The format looks like this:

This is a function description.

Args:
    param1 (str): The first parameter description
    param2 (int): The second parameter description
        This is a continuation of param2 description.
    param3: A parameter without type annotation

Returns:
    str: The return value description

This is an interesting case where doing a partial job can often be worse than doing nothing at all, as the current output is readable but ugly. A partial job may end up being unreadable. I've also received warning that these formats tend to be un(der)specified, and even if they weren't, you need to handle malformed inputs gracefully.

[Gankra]

MVP implemented by astral-sh/ruff#21550