Upd readme

src/test/kotlin/com/igorwojda/tree/classic/traversal/Challenge.kt

@@ -98,7 +98,7 @@ private data class BinaryNode<E : Comparable<E>>(
 )
 
 /*
-We can use queue as helper class to implement breath first traversal. This is not most optimal queue implementation,
+We can use queue as helper class to implement breath first traversal. This is not the most optimal queue implementation,
 however it's enough for this task. Check "Queue challenge" solution for more details and more efficient queue
 implementation.
 */