Is your feature request related to a problem? Please describe.
For modules with mathematical correlations/equations, the code can sometimes be much shorter than the docstring - especially when LaTeX equations and long parameter lists are involved. It's nice to have the option to show the source code in the documentation, as the implementation can be quickly verified, but showing the unformatted docstring source can make this difficult and less readable.

Describe the solution you'd like
It would be beneficial to have an omit_docstring option to go with show_source so that the code block line numbering starts at the first non-whitespace line and continues to the end of the function. I apologize if this is already possible and I missed it somehow.