ncurses 6.2 - patch 20200222

ncurses 6.2 - patch 20200222

+ expanded note in ncurses.3x regarding automatically-included headers
+ improve vt50h and vt52 based on DECScope manual -TD
+ add/use vt52+keypad and vt52-basic -TD
+ check/workaround for line-too-long in Ada95 generate utility when
  building out-of-tree.
+ improve/update HEADER_DEPS in */Makefile.in
+ add "check" rule to include/Makefile, to demonstrate that the headers
  include all of the required headers for the types used.