remove some exports from Broadcast

[vtjnash]

It seems like these were unintentional (and undocumented). Refs #26919.

[mbauman]

andand and oror were exported because the parser generates them; the reason I marked them for export from the Broadcast module was to match the other Broadcast machinery the frontend uses (like broadcasted and materialize). But they're new and can easily go.

broadcast_preserving_zero_d is used elsewhere (and is in 1.3+), but all the uses are fully qualified (both in the stdlib and in the ecosystem).

[StefanKarpinski]

For many syntax lowerings, we lower to a name in the current scope, which allows users to override behavior by defining a different function with a given name. In this case, however, && and || are not overridable syntax, so I don't think it makes sense for .&& or .|| to be overridable (by redefining the andand or oror in the current scope). So it seems like it would be fine for the lowering to emit fully qualified calls to Base.andand and Base.oror so it wouldn't be necessary for these to be exported.

[simeonschaub]

I don't think they were ever exported from Base, they were only exported from the Broadcast submodule.

[StefanKarpinski]

Ah, ok. But still: having lowering emit Base.Broadcast.andand and Base.Broadcast.oror seems best.