[DOC] avoid C++ types in docstrings

[sizmailov]

Here is a small paragraph about docstring generation in pybind11. Also replicates @YannickJadoul 's example from #2263.

I'm not sure if misc.rst is the best place for it.

render

[YannickJadoul]

A few things I would personally phrase slightly differently (up to you to decide if you like it better or not), but looks succinct and good to me!

misc.rst seems find. I don't immediately see another place where we talk about docstrings and signature. It's right underneath the only other section about it ("Generating documentation using Sphinx"), so perfect for me!

Thanks for taking the time to create this, @sizmailov! :-)

[YannickJadoul]

Great, thanks! Let's see if someone else still has something to add. If not, this can go in as-is, afaic :-)

[bstaletic]

@sizmailov Thanks for the PR

[sizmailov]

Thanks everybody for quick and thoughtful reviews with great attention to even subtle things!

[YannickJadoul]

More like, thanks @sizmailov for making this PR and fixing all our minor remarks ;-) Thanks a lot!

[patrislav1]

How to solve this if Foo and Bar are in different pybind11 modules?

EDIT: solved it, Foo just needs additional line py::module_::import("Bar");