Should vecdot broadcast along the contracted axis?

[asmeurer]

The spec implies that it should https://data-apis.org/array-api/latest/API_specification/generated/signatures.linear_algebra_functions.vecdot.html#signatures.linear_algebra_functions.vecdot. However, other functions like matmul do not broadcast along the contracted axis.

This came up in the numpy implementation, which is currently wrong, but is being fixed at numpy/numpy#21928.

[leofang]

tensordot does not allow broadcasting in the contracted axes, so I think vecdot shouldn't, either.