Emacs 31: Issue with C-x binding in comint.el

In Emacs 31, `comint.el` maps "C-x up" to `comint-complete-input-ring`, which breaks my setup. I globally bind "C-x up" to `windmove-up`, but the comint mapping prevents me from using "C-x up" in shell mode. I've solved this by adding the following to my `init.el`:

```elisp
(with-eval-after-load 'comint
  (define-key comint-mode-map (kbd "C-x <up>") 'windmove-up))
```

However, my understanding was that major modes should avoid using the C-x prefix. In fact, mode-specific commands are usually prefixed with C-c, as are all the bindings in `comint.el`, except for this one.

Should I report this as a bug?

-- 
best,

aitor