Add inline edition to user shortcut preferences

The shortcut preferences implemented (or soon to be implemented) in XWIKI-16216 use text inputs. Their design could be improved: the user can activate inline editing for shortcuts. The display looks like a regular text and it changes based on the key pressed.

See https://github.com/xwiki/xwiki-platform/pull/2981#issuecomment-2388611830 for a design reference