`emg3d.TxMagneticDipole` shows wrong coordinates.

[prisae]

> src = emg3d.TxMagneticDipole(coordinates=[0.0, 0.0, 0.0, 0.0, -0.5, 0.5])
> src
TxMagneticDipole: 1.0 A;
    e1={0.0; 0.7; 0.0} m; e2={-0.7; 0.0; 0.0} m

which are just the first two points of it,

> src.points
array([[ 0.        ,  0.70710678,  0.        ],
       [-0.70710678,  0.        ,  0.        ],
       [ 0.        , -0.70710678,  0.        ],
       [ 0.70710678,  0.        ,  0.        ],
       [ 0.        ,  0.70710678,  0.        ]])