A backport of scheme-mode from GNU Emacs 29+

Glenn Morris 8739eb35d9 Add 2011 to FSF/AIST copyright years. 14 年之前
COPYING c25d00bd0e Change to GPLv3. 18 年之前
scheme.el 8739eb35d9 Add 2011 to FSF/AIST copyright years. 14 年之前