I’m not expert on this. But for me, it would make sense to separate the development of the manual and the documentation from julia to somewhere else. I consider that this would follow the philosophy of the “packages” in stdlib which can be now (I don’t know the exact details) updated without “touching” the julia repository.
UPDATE MOTIVATION: Now that 1.0 is relesed, some more effort could go on this direction. If possible, a better documentation and manual will be better for newcomers.