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.
Smex has not been updated since late 2015. Amx was originally a fork of
smex, but as since evolved much further into it's own thing.
Among other things is supports other completing backends, and ivy with
it's fuzzy matching feels rather nice. I'm keeping ido-mode for
everything else, but specifically for M-x I'll give ivy a try.
