ignored_by_productivity description is inaccurate

[Thremtopod]

The description of ignored_by_productivity for both ItemProductPrototype and FluidProductPrototype incorrectly states, "This value is ignored when allow_productivity is false." This is wrong, because it's also relevant for products in a any recipe that can be made in a machine with base productivity (e.g. foundry) or that have a productivity tech. It may also be relevant for surface global productivity, but I've not tested this.

It would actually be useful to mention these cases in the ignored_by_productivity documentation, for two reasons. It'd make it clear that it's possible to "safely" make a recipe with a catalyst in a foundry-like entity; and it'd make it clear how to "protect" a product from having productivity accidentally added by another mod.