(dolist (frame (frame-list))
  (dolist (fontset (fontset-list))
    (set-fontset-font fontset 'unicode (font-spec :name (format "Segoe UI Emoji")) frame 'append)
    (set-fontset-font fontset 'unicode (font-spec :name (format "XITS Math")) frame 'append)))

(setq-default prettify-symbols-alist '(("=>" . 8658) (":=" . 8796)))