Fix articles about arrays in SUMMARY

Author: SamyPesse

SUMMARY.md

@@ -19,8 +19,8 @@
     * [Comparators](conditional/comparators.md)
     * [Concatenate](conditional/concatenate.md)
 * [Arrays](arrays/README.md)
-    * [Indicies](indicies.md)
-    * [Length](length.md)
+    * [Indicies](arrays/indicies.md)
+    * [Length](arrays/length.md)
 * [Loops](loops/README.md)
     * [For](loops/for.md)
     * [While](loops/while.md)