Documentation: Fixed size matrices

[dmillard]

Disclaimer: I've just started using Enoki, and my understanding may be incorrect.

It seems to me that the documentation at https://enoki.readthedocs.io/en/master/matrix.html# may be inaccurate.

Should

using Vector3f = Matrix<float, 3>;
using Vector4f = Matrix<float, 4>;
using Matrix4f = Matrix<float, 4>;

instead be

using Vector3f = Array<float, 3>;
using Vector4f = Array<float, 4>;
using Matrix4f = Matrix<float, 4>;

When I try to use Matrix, as described in the docs, I end up with 3x3 4x4 matrices, rather than 3D and 4D vectors. If I use Array, I get what I expect.

Furthermore, the class documentation makes reference to a Column type parameter, but it seems this isn't consistent with the source.

Thank you for this exciting library!