ncurses 6.4 - patch 20231217

ncurses 6.4 - patch 20231217

+ improve formatting/style of manpages (patches by Branden Robinson).
+ correct an assignment in infocmp "-u" for detecting if a boolean
  is unset in a base entry and set in a use'd chunk, i.e., if it was
  cancelled.
+ modify infocmp "-u" option to not report cancels for strings which
  were already cancelled in a use'd chunk.
+ join two lines in infotocap.3x to eliminate a spurious "description"
  link in installed manpages (report by Sven Joachim).
+ fix typo in NEWS (report by Sven Joachim).
  bold font escapes in manpage cross-references (Debian #1057651).