input-surface: Handle emojis when no input method is in use
Better emoji support for e.g. chromium under XWayland.
Chromium in pure Wayland mode eats the keysyms topmost byte so it wont' work there yet.
I've split this into two commits as it might be useful to revert the more complex part that handles modifiers in when testing why it works/fails on certain clients.
Edited by Guido Günther