A backport of scheme-mode from GNU Emacs 29+

Glenn Morris b96ea47de7 Merge from emacs-23; up to 2012-01-19T07:15:48Z!rgm@gnu.org. 13 gadi atpakaļ
COPYING f42a75b8d8 Restore files that I seem to have mistakenly deleted. 14 gadi atpakaļ
scheme.el b41a5c56cd Add 2012 to FSF copyright years for Emacs files 13 gadi atpakaļ