The functionality associated with the Escape key cannot be rebound to another key

Split from the now-fixed MC-147718 as per request by Mojang.

As it currently is, the Escape key is used for bringing up the game menu, as well as for exiting (or, for nested cases such as options submenus, going “up one level”) whatever user interface is currently “open”. For example, if the pause menu is open, pressing escape will close it.

It is currently not possible to bind either of these functionalities to another button, unlike most of the controls in game.

How to reproduce: note that if something is bound to the Esc key, there is no conflict shown, which shows that there is no other control registered as being bound to it, demonstrating that it is hardcoded.

Note that trying to actually bind something to the Esc key will simply unbind it instead. This is a separate issue that I will report separately. The demonstrational screenshot attached to this ticket was achieved via options.txt editing, showing that there exists functionality for binding to this key, as well as an existing translation string.

To fix: make Escape’s functionality rebindable - either both the “open game menu” and “exit current menu” functionalities should be classed under the same thing, or they should be two separate, individually rebindable controls which are both bound to Escape by default.