cli/env: remove ignored vars retroactively
cli/env: remove ignored vars retroactively

doom-env-ignored-vars is now treated as a list of regexps.

Also updates docstrings and announces ignored variables.

hlissner/doom-emacs,hlissner/.emacs.d,UndeadKernel/emacs_doom,hlissner/.emacs.d,UndeadKernel/emacs_doom,UndeadKernel/emacs_doom,UndeadKernel/emacs_doom,UndeadKernel/emacs_doom,hlissner/.emacs.d,hlissner/doom-emacs,hlissner/.emacs.d,hlissner/doom-emacs,hlissner/doom-emacs,hlissner/doom-emacs,hlissner/.emacs.d,UndeadKernel/emacs_doom,hlissner/doom-emacs,hlissner/.emacs.d,hlissner/.emacs.d,UndeadKernel/emacs_doom,hlissner/.emacs.d,hlissner/doom-emacs