💥 revise hook/var fns naming convention (2/2)

This is second of three big naming convention changes. In this commit,
we change the naming conventions for hook functions and variable
functions:

1. Replace the bar | to indicate a hook function with a -h suffix, e.g.

     doom|init-ui -> doom-init-ui-h
     doom|run-local-var-hooks -> doom-run-local-var-hooks-h

2. And add a -fn suffix for functions meant to be set on variables,
   e.g.

     (setq magit-display-buffer-function #'+magit-display-buffer-fn)

See ccf327f8 for the reasoning behind these changes.

modules/term/eshell/autoload/eshell.el

@@ -106,7 +106,7 @@
             (evil-change-to-initial-state))
           (goto-char (point-max)))
       (with-current-buffer (pop-to-buffer eshell-buffer)
-        (doom|mark-buffer-as-real)
+        (doom-mark-buffer-as-real-h)
         (if (eq major-mode 'eshell-mode)
             (run-hooks 'eshell-mode-hook)
           (eshell-mode))

modules/term/eshell/config.el

@@ -73,7 +73,7 @@ You should use `set-eshell-alias!' to change this.")
         eshell-error-if-no-glob t)
 
   ;; Consider eshell buffers real
-  (add-hook 'eshell-mode-hook #'doom|mark-buffer-as-real)
+  (add-hook 'eshell-mode-hook #'doom-mark-buffer-as-real-h)
 
   ;; Keep track of open eshell buffers
   (add-hook 'eshell-mode-hook #'+eshell|init)