Instead of having a separate start.lua.in file in the scripts directory
and no start.lua file in data/core we use the file data/core/start.lua
as a template for Meson to generate the final start.lua file for release.
In this way people naturally trying to run lite-xl from the source folder
will have a start.lua file albeit without a resolved version number.
Otherwise, when using run-local script or the meson install command the
meson-generated start.lua file will be used as it should be.