Fix notation typo
Do some coercion proofs by duality.

We only gain 3s overall, but we shifted some time from special-purpose
code (coercions between [AdjunctionCounit] and [AdjunctionUnitCounit])
to slightly more general purpose code (duality things).  And if we ever
get eta on records in Coq, most of the duality code can disappear.  So
I'm going to call it a win overall.

After    | File Name                             | Before
-----------------------------------------------------------
0m23.90s | Category/Equality                     | 0m22.67s
0m22.52s | Adjoint/Hom                           | 0m21.50s
0m21.69s | Comma/Duals                           | 0m22.06s
0m12.11s | Adjoint/Composition                   | 0m12.85s
0m12.04s | Adjoint/UniversalMorphisms            | 0m12.08s
0m11.40s | Adjoint/Duals                         | 0m08.50s
0m10.56s | Adjoint/UnitCounitCoercions           | 0m23.36s
0m08.73s | Comma/InducedFunctors                 | 0m07.86s
0m07.19s | Groupoid                              | 0m07.49s
0m06.66s | Adjoint/Equality                      | 0m06.68s
0m05.64s | Adjoint/UnitCounit                    | 0m00.27s
0m05.25s | Category/Morphisms                    | 0m05.48s
0m04.74s | SumPreCategory                        | 0m04.58s
0m04.26s | Groupoid/Duals                        | 0m04.85s
0m04.18s | Functor/Equality                      | 0m04.02s
0m03.89s | Groupoid/Functors                     | 0m03.92s
0m03.72s | UniversalProperties                   | 0m03.22s
0m02.78s | Grothendieck/ToSet                    | 0m02.80s
0m02.66s | BoolCategory                          | 0m02.58s
0m02.62s | Comma/CommaCategory                   | 0m02.45s
0m01.97s | Category/Product                      | 0m01.89s
0m01.91s | NaturalTransformation/Duals           | 0m01.96s
0m01.85s | Hom                                   | 0m01.72s
0m01.84s | NaturalTransformation/Equality        | 0m01.87s
0m01.49s | NaturalTransformation/Product         | 0m01.36s
0m01.37s | NaturalTransformation/Composition     | 0m01.27s
0m01.26s | NaturalTransformation/CompositionLaws | 0m01.21s
0m01.23s | Functor/Product                       | 0m01.41s
0m01.11s | NaturalTransformation/Isomorphisms    | 0m01.19s
0m00.77s | Cat/Morphisms                         | 0m00.79s
0m00.65s | FunctorCategory/Morphisms             | 0m00.80s
0m00.57s | InitialTerminalCategory               | 0m00.63s
0m00.47s | Functor/CompositionLaws               | 0m00.45s
0m00.44s | Comma/Projection                      | 0m00.39s
0m00.40s | SetCategory                           | 0m00.31s
0m00.38s | Discrete/Duals                        | 0m00.42s
0m00.33s | IndiscreteCategory                    | 0m00.37s
0m00.33s | Common                                | 0m00.34s
0m00.31s | Cat                                   | 0m00.34s
0m00.31s | NaturalTransformation/Identity        | 0m00.26s
0m00.30s | Functor/Duals                         | 0m00.29s
0m00.28s | Category/Objects                      | 0m00.26s
0m00.27s | Functor/Composition                   | 0m00.24s
0m00.25s | FunctorCategory                       | 0m00.26s
0m00.23s | NatCategory                           | 0m00.27s
0m00.21s | IsGroupoid                            | 0m00.21s
0m00.20s | NaturalTransformation/Core            | 0m00.14s
0m00.19s | Category/Core                         | 0m00.20s
0m00.18s | ComputableCat                         | 0m00.17s
0m00.17s | NatCategory/Duals                     | 0m00.23s
0m00.17s | NaturalNumbersObject                  | 0m00.14s
0m00.17s | Category/Duals                        | 0m00.15s
0m00.15s | Adjoint/Identity                      | 0m00.16s
0m00.14s | Adjoint                               | 0m00.17s
0m00.13s | Category/UnivalentCategory            | 0m00.13s
0m00.12s | NaturalTransformation                 | 0m00.09s
0m00.12s | Functor                               | 0m00.09s
0m00.12s | DiscreteCategory                      | 0m00.10s
0m00.11s | Peano                                 | 0m00.11s
0m00.10s | Functor/Core                          | 0m00.11s
0m00.10s | Utf8                                  | 0m00.11s
0m00.10s | Grothendieck                          | 0m00.12s
0m00.09s | Category                              | 0m00.07s
0m00.09s | Category/StrictCategory               | 0m00.09s
0m00.08s | Functor/Identity                      | 0m00.10s
0m00.04s | NotationsUtf8                         | 0m00.05s
0m00.04s | Notations                             | 0m00.02s
-----------------------------------------------------------
3m19.67s | Total                                 | 3m22.28s