And add a verification step to the emoji data generator to ensure all
emoji are listed in this file. This file will be used as a sources list
in both the CMake and GN build systems.
It is probably possible to generate this list. But in a first attempt,
the CMake code to set the file as a dependency of a pseudo target, which
would then parse the file and install the listed emoji was getting quite
verbose and complicated. So for now, let's just maintain this list.