rpc: add rpc v2 chainSpec to polkadot (#2859)

The [chainSpec RPC API from the v2
spec](https://paritytech.github.io/json-rpc-interface-spec/api/chainSpec.html)
was only added to substrate-node and should be added to polkadot as well

/cc @lexnv

substrate/primitives/core/src/address_uri.rs

@@ -184,7 +184,7 @@ impl<'a> AddressUri<'a> {
 					Error::in_pass(initial_input, initial_input_len - input.len())
 				} else {
 					Error::in_phrase(initial_input, initial_input_len - input.len())
-				});
+				})
 			}
 		}