Delete trailing whitespace, globally, by default

Also adds doom|disable-delete-trailing-whitespace hook, which can be
used to disable this behavior on a per-buffer basis. If you want to turn
off this global behavior:

  (remove-hook 'write-file-functions #'delete-trailing-whitespace)

core/autoload/editor.el

@@ -281,6 +281,14 @@ with weak native support."
 
 ;;;###autoload
 (defun doom|enable-delete-trailing-whitespace ()
-  "Enables the automatic deletion of trailing whitespaces upon file save, by
+  "Enables the automatic deletion of trailing whitespaces upon file save.
-attaching `delete-trailing-whitespace' to a buffer-local `before-save-hook'."
+
-  (add-hook 'before-save-hook #'delete-trailing-whitespace nil t))
+i.e. adds `delete-trailing-whitespace' to `write-file-functions', buffer-locally."
+  (add-hook 'write-file-functions #'delete-trailing-whitespace nil t))
+
+;;;###autoload
+(defun doom|disable-delete-trailing-whitespace ()
+  "Disables the automatic deletion of trailing whitespaces upon file save.
+
+i.e. removes  `delete-trailing-whitespace' from `write-file-functions'."
+  (remove-hook 'write-file-functions #'delete-trailing-whitespace t))

core/core-editor.el

@@ -81,6 +81,11 @@ fundamental-mode) for performance sake."
 
 (add-hook 'after-save-hook #'executable-make-buffer-file-executable-if-script-p)
 
+;; Deleting trailing whitespace is on by default, but must be set on
+;; write-file-functions, so that editorconfig can see it (so it doesn't add it
+;; redundantly and can remove it when needed).
+(add-hook 'write-file-functions #'delete-trailing-whitespace)
+
 ;; revert buffers for changed files
 (def-package! autorevert
   :after-call after-find-file

modules/lang/emacs-lisp/config.el

@@ -50,7 +50,7 @@
 
   (add-hook! 'emacs-lisp-mode-hook
     #'(;; 3rd-party functionality
-       auto-compile-on-save-mode doom|enable-delete-trailing-whitespace
+       auto-compile-on-save-mode
        ;; fontification
        rainbow-delimiters-mode highlight-quoted-mode
        ;; initialization

modules/lang/racket/config.el

@@ -18,12 +18,7 @@
 
   (setq racket-smart-open-bracket-enable t)
 
-  (add-hook! racket-mode
+  (add-hook! racket-mode #'(rainbow-delimiters-mode highlight-quoted-mode))
-    #'(;; 3rd-party functionality
-       doom|enable-delete-trailing-whitespace
-       ;; fontification
-       rainbow-delimiters-mode
-       highlight-quoted-mode))
 
   (map! :map racket-mode-map
         :localleader