tools/flycheck: prevent flycheck popup buffer taking focus
tools/flycheck: prevent flycheck popup buffer taking focus

When tooltip/childframe is off, long errors can spawn a popup window
that, by default, will steal input focus. No more!

Reported by @rgrinberg

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