[pdsl_model] Make use of $crate inside state! and messages!

model/src/msg.rs

@@ -29,7 +29,7 @@ macro_rules! messages {
 		#[derive(Copy, Clone)]
 		struct $msg_name;
 
-		impl pdsl_model::Message for $msg_name {
+		impl $crate::Message for $msg_name {
 			type Input = ($($param_ty),*);
 			type Output = $ret_ty;
 

model/src/state.rs

@@ -64,7 +64,7 @@ macro_rules! state {
 			}
 		}
 
-		impl pdsl_model::ContractState for $state_name {
+		impl $crate::ContractState for $state_name {
 			const NAME: &'static [u8] = stringify!($state_name).as_bytes();
 		}
 	};