Enhance ZON parser to support tuples and update documentation

- Modify parser to handle ZON tuples (`.{ 1, 2, 3 }`) as arrays
- Update README with more detailed explanation of ZON tuple syntax
- Add multiple example ZON files demonstrating tuple usage
- Implement tuple parsing in `parser.py`
- Add test case for tuple parsing

examples/simple_nested.zon

@@ -0,0 +1,4 @@
+.{
+    .simple_tuple = .{ 1, 2, 3 },
+    .nested_tuple = .{ .{ 1, 2 }, .{ 3, 4 } },
+}