I've set `lexical-binding` to `nil` in all Emacs Lisp files to suppress
the warnings introduced in Emacs 31 requiring all elisp files to have a
`lexical-binding` comment.
This retains the default behavior of dynamic binding when no
`lexical-binding` comment is present. With it set to `t` across the
board, various things break, and fixing those is a task for another day.
This is to ensure it stay up to date with the siren-shift-text module,
which is currently the module I use for shifting text left/right. At
some point I will re-evaluate the smart-shift package.