docs(factor): update stale Player reference to Rating

Follow-up to the Player→Rating rename (2f5aa98); a doc comment in
team_sum.rs still referenced Player::performance().

src/factor/team_sum.rs

@@ -6,8 +6,8 @@ use crate::{
 
 /// Computes the weighted sum of player performances into a team-perf var.
 ///
-/// Inputs are pre-computed player performance Gaussians (i.e., player priors
-/// already with beta² noise added via `Player::performance()`). The factor
+/// Inputs are pre-computed player performance Gaussians (i.e., rating priors
+/// already with beta² noise added via `Rating::performance()`). The factor
 /// runs once per game and writes the weighted sum to the output var.
 #[derive(Debug)]
 #[allow(dead_code)]