Add Reverse String in Wren (#4390)

Author: Kaamkiya

archive/w/wren/reverse-string.wren

@@ -0,0 +1,15 @@
+import "os" for Process
+
+var args = Process.arguments
+
+if (args.count < 1) {
+  args.add("")
+}
+
+var rev = ""
+
+for (c in args[0]) {
+  rev = c + rev
+}
+
+System.print(rev)