PR 4251 converts most of functions in the _curses and _curses_panel modules (around 130 functions) to Argument Clinic. Many functions didn't have docstrings, the PR adds them. You can test new signatures and docstrings by the following commands:

./python -m pydoc curses
./python -m pydoc curses.window
./python -m pydoc curses.panel
./python -m pydoc curses.panel.panel

3 functions can't be converted. The initial versions of Argument Clinic supported such declarations, but now it doesn't support them. Will try to fix Argument Clinic in other issue. Yet 35 generated window methods have not been converted because I'm too tired by this patch. They will be converted by other patches.

I tried to make new and existing docstrings short and clear, but I think many docstrings still need editing.