Reseted the simplification for de-referencing.

exercises/046_optionals2.zig

@@ -48,7 +48,7 @@ pub fn main() void {
 // If e1 and e2 are valid pointers to elephants,
 // this function links the elephants so that e1's tail "points" to e2.
 fn linkElephants(e1: ?*Elephant, e2: ?*Elephant) void {
-    e1.?.tail = e2;
+    e1.?.*.tail = e2.?;
 }
 
 // This function visits all elephants once, starting with the