[MLton] Universal type wiki page wrong?

[Henry Cejtin]

I agree.
The text should also be made more clear.  The statement
	project returns an option because it may be applied to an element
	in the universal type not created by inject.
means that given a particular (inject, project) pair which was the result
of calling embed, that particular project, applied to a value of the
universal type must return NONE if the value did not come from calling
that particular inject.