Add keyboard shortcuts to focus previous/next message (A11y)

[ghost]

Your use case

What would you like to do?

I'd like to add keyboard shortcuts to focus the previous/next message in chat (not to edit the previous/next message you sent)

Why would you like to do it?

Currently, the only way to navigate to a message via the keyboard is to use Tab/Shift-Tab. But this cycles through each read indicator, the React/Reply/Etc. popup, and avatar before finally focusing the previous/next message, which takes several presses. This is bad for accessibility - anyone who can't use a mouse for whatever reason will find it frustrating to interact with messages (and painful, if they have RSI).

How would you like to achieve it?

Either rebind the Up and Down keys, which currently navigate between editable messages, to instead navigate between all messages, or add a new pair of keyboard shortcuts for this function.

Have you considered any alternatives?

No response

Additional context

No response

[aaronraimist]

Related: #10733

[fcnjd]

Hello all,
I'd like to use the opportunity to emphasize that we from the blind community, who use a screenreader daily, would consider this festure essential to scroll in a chat history. Now that issue #20099 got closed, this is still an important thing. Please consider making a fix for that, otherwise the virtual cursor of a screenreader jumps around wildly in a long chat history, making it impossible to read it through.

[t3chguy]

Related #25123