2.16.0

CHANGES:

• Add support for OCaml 5.4 (#500, @Octachron, @anmonteiro)
• restore backtrace (#503, fixes #501, @ysalmon)
• support camlp$n preprocessor (#486, fixes #485, @aqjune)
• utop configuration and state files (utoprc, utop-history) are now always in the relevant
  utop subdirectory (#484, fixes #478, #481 and #499, @tuohy).
• fix emacs completion for qualified paths (Module.M.some_name) (#497, fix #455, @juergenhoetzel, @bbatsov)
• implicit bindings for emacs mode (#465, fix #412, @bencef)