21: Added path function to TreeNode (#22)

Path refers to the sequence of nodes along the edges of a tree.

src/jvmMain/kotlin/Example.ws.kts

@@ -0,0 +1,14 @@
+import com.github.adriankuta.datastructure.tree.tree
+
+val root =
+    tree("World") {
+        child("North America") {
+            child("USA")
+        }
+        child("Europe") {
+            child("Poland")
+            child("Germany")
+        }
+    }
+
+print(root.prettyString())