message: some fixes and small improvements
diff: @@ -621,9 +621,9 @@ impl Spotify {
  let offset = offset.map(|s| s.to_string());
  let params = build_map! {
  opt fields,
  + opt market => market.as_ref(),
  opt limit => &limit,
  opt offset => &offset,
  - opt market => market.as_ref(),
  };
  let url = format!("playlists/{}/tracks", playlist_id.id());
  @@ -745,10 +745,10 @@ impl Spotify {
  track_ids: impl IntoIterator<Item = &'a TrackId>,
  ) -> ClientResult<()> {
  let uris = track_ids.into_iter().map(|id| id.uri()).collect::<Vec<_>>();
  -
  let params = build_json! {
  - req uris => uris
  + req uris
  };
  +
  let url = format!("playlists/{}/tracks", playlist_id.id());
  self.endpoint_put(&url, &params).await?;
  @@ -1063,8 +1063,8 @@ impl Spotify {
  let limit = limit.map(|s| s.to_string());
  let params = build_map! {
  req r#type => Type::Artist.as_ref(),
  - opt after => &after,
  - opt limit => &limit,
  + opt after,
  + opt limit,
  };
  let result = self.endpoint_get("me/following", &params).await?;
  @@ -1447,9 +1447,9 @@ impl Spotify {
  let limit = limit.map(|x| x.to_string());
  let offset = offset.map(|x| x.to_string());
  let params = build_map! {
  + opt market => market.as_ref(),
  opt limit => &limit,
  opt offset => &offset,
  - opt market => market.as_ref(),
  };
  let result = self.endpoint_get("browse/new-releases", &params).await?;
  @@ -1809,7 +1809,7 @@ impl Spotify {
  Offset::Position(position) => json!({ "position": position }),
  Offset::Uri(uri) => json!({ "uri": uri.uri() }),
  },
  - opt position_ms => position_ms
  + opt position_ms,
  };
  @@ -2120,9 +2120,9 @@ impl Spotify {
  let limit = limit.map(|x| x.to_string());
  let offset = offset.map(|x| x.to_string());
  let params = build_map! {
  + opt market => market.as_ref(),
  opt limit => &limit,
  opt offset => &offset,
  - opt market => market.as_ref(),
  };
  let url = format!("shows/{}/episodes", id.id());
  @@ -2191,7 +2191,7 @@ impl Spotify {
  ) -> ClientResult<Vec<bool>> {
  let ids = join_ids(ids);
  let params = build_map! {
  - req ids => ids.as_str(),
  + req ids => &ids,
  };
  let result = self.endpoint_get("me/shows/contains", &params).await?;
  self.convert_result(&result)
  