Don't warn on empty modules when scanning API
Update API doc skip patterns
Clean up numpydoc section headers
Various minor docs fixes
Use new format for intersphinx mapping
Various docs fixes
Miscellaneous docs fixes
More fixes to doc formatting
Correct %edit docstring for ZMQ shell
fix history trim backup flag doc
add --keep alias for history trim
fix nbconvert completion

thanks @jakobgager for pointing this out in #4528
Produce rst-compatible options lists from magic_arguments
Fix documentation of functions using magic_arguments
Use Sphinx autosummary extension for API docs index
Tidy up a few more warnings from Sphinx
add note about the 1000 / --keep variable
bash completion: proper history completion
custom keyboard interrupt handling in  ask_yes_no

Sometimes, Ctrl-C just makes sense as an answer, and re-asking the
question is just frustrating. This changes makes it possible to break
out of the asking loop via Ctrl-C. This is particularly handy for asking
questions from the command line, where one expects Ctrl-c to be a sort
of "Cancel" operation, and is often functionally equivalent to "no"
allow trimming to an empty database (--keep=0)