These files need to be loaded as resources with PyOxidizer, instead of using
filesystem representations. AFAICT, the resource loading mechanisms only work
for the named package given to it, and can't reach into a subdirectory.
While here, the help directory is renamed to helptext. Without this, trying
to load external help text crashed in mercurial/help.py when importing .i18n,
saying there's no mercurial.help.i18n module.