fix formatting issues

Author: lennart

src/main/java/com/thealgorithms/tree/CentroidDecomposition.java

@@ -154,7 +154,7 @@ public void findCentroid(int src, int previousCentroid) {
         }
 
         for (int node : tree[src]) {
-            if (!centroidMarked[node]) findCentroid(node, src);                
+            if (!centroidMarked[node]) findCentroid(node, src);           
         }
     }
 

src/test/java/com/thealgorithms/tree/CentroidDecompositionTest.java

@@ -222,7 +222,7 @@ private static void assertValidCentroidTree(CentroidDecomposition cd, int n) {
         assertEquals(1, roots, "must have exactly one root");
         assertEquals(n - 1, edges, "centroid tree must have n-1 edges");
     }
-    
+
     private static void copyEdges(CentroidDecomposition from, CentroidDecomposition to) {
         to.addEdgeTree(0, 1);
         to.addEdgeTree(0, 2);