mathlib3

348a674b - feat(algebra/algebra/subalgebra/basic): Swap arguments of `map` and `comap` (#15744)

feat(algebra/algebra/subalgebra/basic): Swap arguments of `map` and `comap` (#15744) As suggested by @eric-wieser, I swapped the arguments of `subalgebra.map` and `subalgebra.comap`. I also updated `subalgebra.map_injective` to use `function.injective` and to have `f` implicit. This is done to make the `subalgebra` API match the `subgroup`, `submodule`, etc... API.