duplicate instances in docs?

Stream: mathlib4

[Jireh Loreaux]

@Henrik Böving, I think there is a bug in the portion of the docs that creates the "Instances for" lists. I am seeing many duplicates. Just as an example, look at docs#Matrix, but I've seen it on others as well.

[Henrik Böving]

That is interesting indeed, I will take a look

[Henrik Böving]

@Jireh Loreaux done and deployed