Fix link to second and first in Strong Profunctor laws targeting Arrow

[lemastero]

In Strong Profunctor laws there are references to first and second from Arrow:

lmap fst ≡ rmap fst . first'
lmap (first f) . second' ≡ rmap (first f) . second'

but they should link to Strong first' and second'

lmap fst ≡ rmap fst . first'
lmap (first' f) . second' ≡ rmap (first' f) . second'