Some modules don't expose error definitions to chain metadata

[bddap]

dock-substrate/runtime/src/attest.rs

Line 75 in 441c912

pub struct Module<T: Trait> for enum Call where origin: T::Origin {

for example needs the line: type Error = Error<T>;

Without these error definitions, extrinsic submission errors are indecipherable by users. Example:

Extrinsic failed submission: [{"Module":{"index":18,"error":1}},{"weight":290004400,"class":"Normal","paysFee":"Yes"}]

[herou]

@bddap Can I tackle this one?

[bddap]

@lovesh, is code owner here. What do you think @lovesh.

[lovesh]

Hi @bddap . Yes.