refactor(category_theory/adjunction/mates): faster proof (#6116)
Co-authors: `lean-gptf`, Stanislas Polu
elaboration 750ms -> 350ms
5X smaller proof term
This was found by `formal-lean-wm-to-tt-m1-m2-v4-c4` when we evaluated it on theorems added to `mathlib` after we last extracted training data.