Use native Emacs completion in shell mode

Evaluating INSIDE_EMACS might also be helpful in setting a usable prompt, even if TERM is "dumb".

init.el

@@ -2543,12 +2543,7 @@ eventuelly be set to nil, however)."
               comint-scroll-show-maximum-output t
               comint-completion-addsuffix t
               comint-buffer-maximum-size 100000
-              comint-input-ring-size 5000)
-  :config (progn
-            ;; Never let bash know that we are inside Emacs;
-            ;; cf. https://coredumped.dev/2020/01/04/native-shell-completion-in-emacs/
-            (advice-add 'comint-term-environment
-                        :filter-return #'(lambda (env) (cons "INSIDE_EMACS" env)))))
+              comint-input-ring-size 5000))
 
 (use-package term
   :commands (term-send-string