Upstream moved from 'C-[' and 'C-]' to 'C-{' and 'C-}', which are more difficult to type and still conflict with org-mode's default bindings. This patch fulfills user expectations for the principle of least surprise. Olivetti for Debian also preserves the established 'C-c \' binding for olivetti-set-width for better ergonomics and the principle of least surprise.
