Find an example for using the MF-MF relation causally upstream of, negative effect

[vanaukenk]

To complete our MF-MF relations documentation on the wiki we still need an example for causally upstream of, negative effect.

[vanaukenk]

We've added a statement to the wiki page for this relation, and its positive sibling, to indicate that we don't have examples, curators should use a more specific relation whenever possible, and if they have an example, they should bring it to an annotation call.