[Format][Docs] Document primitive types in the Arrow format docs

[ianmcook]

Describe the enhancement requested

It would be nice if the Arrow columnar format docs page documented what primitive types Arrow supports. It is not great that readers need to go to format/Schema.fbs for that information today.

Component(s)

Documentation, Format

[Amishakumari544]

can somebody tell me where I should add this Schema in Arrow columnar page? @ianmcook @westonpace ?

[westonpace]

I'll let @ianmcook answer this as I'm not actually sure what "primitive types" is referring to. I think, when I marked this, I assumed he was talking about logical types. Perhaps #14752 would actually be a better starting point. That issue is about replacing this paragraph with a brief listing of these types. For example, it is not clear in the document that Arrow supports a "boolean" type. One must refer to the schema to figure this out. (the document describes the physical layout, "fixed-size primitive", and the schema defines the type "Bool")

Another place we have a listing of logical types is at https://arrow.apache.org/docs/status.html#data-types . So I think the idea is to just have a listing of data types in the "arrow columnar format" page.

[jorisvandenbossche]

I think in this context the "primitive types" and "logical types" are meaning the same (confusingly), as we currently only have a section "Fixed-size Primitive Layout explaining the layout of primitive types, but not which actual "logical" primitive types we have (whether the term "logical" is correct here is another question).

So essentially I think this issue is about exactly the same as #14752, I think we can close this one as duplicate of #14752?
Unless we would like to list just the primitive types that follow the fixed-size primitive layout in that section, instead of listing all types (including those primitive types) in the "Logical types" section?

[ianmcook]

Duplicate of #14752