commands: add response types for multiple commands

src/commands/queue/playlist.rs

@@ -1,4 +1,7 @@
+use serde::{Deserialize, Serialize};
+
 use crate::{
+    Uri,
     commands::{Command, CommandResponse, ResponseParserError, empty_command_request},
     response_tokenizer::ResponseAttributes,
 };
@@ -7,7 +10,8 @@ pub struct Playlist;
 
 empty_command_request!(Playlist, "playlist");
 
-pub struct PlaylistResponse();
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct PlaylistResponse(Vec<Uri>);
 
 impl CommandResponse<'_> for PlaylistResponse {
     fn into_response_enum(self) -> crate::Response {