f clarify comment

Author: TheBlueMatt

lightning/src/routing/router.rs

@@ -209,7 +209,8 @@ struct PathBuildingHop {
 	#[cfg(test)]
 	// In tests, we apply further sanity checks on cases where we skip nodes we already processed
 	// to ensure it is specifically in cases where the fee has gone down because of a decrease in
-	// valud_contribution_msat, which requires tracking it here.
+	// value_contribution_msat, which requires tracking it here. See comments below where it is
+	// used for more info.
 	value_contribution_msat: u64,
 }