fixed linting

Author: DanielLacina

src/cluster/agglomerative.rs

@@ -98,8 +98,8 @@ impl<TX: Number, TY: Number, X: Array2<TX>, Y: Array1<TY>> AgglomerativeClusteri
             return Err(Failed::because(
                 FailedError::ParametersError,
                 &format!(
-+                    "n_clusters: {n_clusters} cannot be greater than n_samples: {num_samples}"
-+                ),
+                    "n_clusters: {n_clusters} cannot be greater than n_samples: {num_samples}"
+                ),
             ));
         }