Combine keymaps so a key bound by more than one of them tries each binding
in turn, earliest first, until one consumes the event.
Spreading them into one object instead would keep only the last binding for
a shared key, which is silent: the editor still works, one extension's
handling of that key simply never runs again. Enter is bound by both the
table and the block keymaps, and that is exactly how it would go missing.
Combine keymaps so a key bound by more than one of them tries each binding in turn, earliest first, until one consumes the event.
Spreading them into one object instead would keep only the last binding for a shared key, which is silent: the editor still works, one extension's handling of that key simply never runs again. Enter is bound by both the table and the block keymaps, and that is exactly how it would go missing.