ncurses 6.3 - patch 20220226

+ fix issues found with coverity:
  + rewrite canonical_name() function of infocmp to ensure buffer size
  + corrected use of original tty-modes in tput init/reset subcommands
  + modify tabs program to limit tab-stop values to max-columns
  + add limit-checks for palette rgb values in test/ncurses.c
+ add a few null-pointer checks to help with static-analysis.
+ enforce limit on number of soft-keys used in c++ binding.
+ adjust a buffer-limit in write_entry.c to quiet a bogus warning from
  gcc 12.0.1