+ update man/curs_memleaks.3x, to include <term.h> which declares
exit_terminfo.
+ clarify man/curs_terminfo.3x, to mention why the macro setterm is
defined in <curses.h>, and remove it from the list of prototypes
(prompted by patch by Graeme McCutcheon).
+ amend man/curs_terminfo.3x, to note that <curses.h> is required
for certain functions, e.g., those using chtype or attr_t for
types, as well as mvcur (cf:
20201031).
+ use parameter-names in prototypes in curs_sp_funcs.3x, for
consistency with other manpages.