Emacs 27.x has been the stable version of Emacs for nearly a year, and
introduces a litany of bugfixes, performance, and quality-of-life
improvements that significantly reduce Doom's maintenance burden (like
XDG support, early-init.el, image manipulation without imagemagick, a
native JSON library, harfbuzz support, pdumper, and others).
With so many big changes on Doom's horizon, I like having one less (big)
thing to worry about.
Also reverts bb677cf7a (#5232) as it is no longer needed.