[pocket] Add buttons for previously entered text

When you open the chat, pressing UP and DOWN on the keyboard enters previously entered text, which is especially useful for commands. It works in Java and it works in Bedrock as well, you just need a physical keyboard. There should be a way to do this on a touchscreen as well, the simplest solution that comes to mind is just “up” and “down” buttons next to the input field. Re-typing commands is always a pain in the A, and it applies twice with an on-screen keyboard.

I’ve made two concepts how this could be done, the bigger buttons would probably be easier to tap, but the smaller ones might work for bigger screens: https://i.imgur.com/xFk8cvz.png

Thank you for voting for this simple yet very needed feature!