Re-evaluate default docstrings

[jpfeuffer]

Currently, we do:

  Cython implementation: ...
  Cython implementation: ...

  Documentation can be found here: $URL$

  $Additional wrap-doc$

First: I think autodoc-docstring-signatures would be much more helpful than the Cython implementations. We have the code to generate the signatures already from the typestub support.

Second: We should use Markdown or RST to not spell out the whole URL.

Third: A link to the actual PXD, based on a parameterizable root URL would be nice.

Fourth: Sometimes indentation and newlines after the default docstring and the additional wrap-docs is missing.

[jpfeuffer]

First has been implemented in #166
Second had to be and has been implement in OpenMS directly.
I think Fourth is also solved.