Applicable to ink! trait implementation blocks.

Applied on ink! trait implementation blocks to disambiguate other trait implementation blocks with equal names.

Example

#[ink(namespace = "my_namespace")]
impl MyTrait for MyStorage {
    #[ink(message)]
    fn my_message(&self) {}
}

This changes the resulting selectors of all the ink! messages and ink! constructors within the trait implementation. Thus allowing disambiguation between trait implementations with overlapping message or constructor names.