Support any array length via const generics

[archseer]

1.51 stabilized support for const generics on arrays, that way array length can be supported.

I had the need for [u8; 65] (64 byte signature + nonce) but had to rely on Vec<u8> for now since we currently only generate implementations for sizes 1-32.

[GREsau]

This is a similar problem to serde-rs/serde#1937 - serde implements Serialize for [T; 0] even when T doesn't implement Serialize, so I followed the same pattern with JsonSchema. Unfortunately, this makes it difficult to use const generics, because in the general case, [T; n] requires T: JsonSchema, which would then mean that [T; 0] would also require T: JsonSchema.

That would be a breaking change (which we can do in 1.0), and a divergence from how serde works, although I don't think it's unreasonable - after all, how often to people really generate a JSON schema for [T; 0] where T doesn't implement JsonSchema?

But out of interest, what's your use-case? As I understand it, you can't be using serde to serialize/deserialize that type because it doesn't use const generics?