Missing `inner` and `outer` functions

MLX allows for calculating the `inner` and `outer` products for vectors.

* https://ml-explore.github.io/mlx/build/html/python/_autosummary/mlx.core.inner.html
* https://ml-explore.github.io/mlx/build/html/python/_autosummary/mlx.core.outer.html

These functions were added here: https://github.com/ml-explore/mlx/pull/348