* `bindsym --to-code` enables keysym to keycode translation.
* If there are no `xkb_layout` commands in the config file, the translation
uses the XKB_DEFAULT_LAYOUT value.
* It there is one or more `xkb_layout` command, the translation uses
the first one.
* If the translation is unsuccessful, a message is logged and the binding
is stored as BINDING_KEYSYM.
* The binding keysyms are stored and re-translated when a change in the input
configuration may affect the translated bindings.