Make the crash warning in ctypes more prominent

[StanFromIreland]

(I was in a warning-y mood today ;-)

I agree with Jelle:

The note you cite in the ctypes docs is buried in a section about a more specific topic (calling functions). I think it's worth adding a more prominent warning like the one on https://docs.python.org/3/library/pickle.html . However, once we do that I don't think we need to do anything in the devguide: the note in the CPython docs should be enough.

Originally posted by @JelleZijlstra in #211

[read-the-docs-community]

Documentation build overview

📚 cpython-previews | 🛠️ Build #32852780 | 📁 Comparing 0b1a090 against main (c714b56)

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2 files changed

± library/ctypes.html
± whatsnew/changelog.html

[JelleZijlstra]

I like this wording! Please leave this open for a little bit to give others a chance to comment though.