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 involved always loading `helm-config` which sets up
`helm-command-prefix` and `helm-command-map` allowing use-package to set
bindings on the map all without loading anything else until needed.
