Command used:
  perl -pi -e 's/ (\d{4}-)?(2022)(?= Free Software)/
               " ".($1||"$2-").($2+1)/e' **/*(^/)
under zsh, reverting doc/texinfo.tex (copied from GNU Texinfo)
and the tools/mbench directory (not distributed with MPFR).
Removed 2022 from the example in the doc/README.dev file.

(cherry picked from commit aff171ac)