gh-151776: Add curses state-query functions (GH-151778)

gh-151776: Add curses state-query functions (GH-151778)

Add window methods and module functions that report curses state which could
previously only be set: the window getters is_cleared(), is_idcok(),
is_idlok(), is_immedok(), is_keypad(), is_leaveok(), is_nodelay(),
is_notimeout(), is_pad(), is_scrollok(), is_subwin(), is_syncok(),
getdelay(), getparent() and getscrreg(), and the functions is_cbreak(),
is_echo(), is_nl() and is_raw().  They are available when built against an
ncurses with NCURSES_EXT_FUNCS.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>