docs: fail check if not all the <FILE>s are actually XIncluded
docs: fail check if not all the <FILE>s are actually XIncluded

This catches the error fixed in the previous commit.

Distrotech/telepathy-glib,Distrotech/telepathy-glib,Distrotech/telepathy-glib,Distrotech/telepathy-glib,Distrotech/telepathy-glib