Update README.md

Author: 4meepo

README.md

@@ -92,7 +92,7 @@ type SortExample struct {
 
 The fixed order is `json,xml`, so the tags `json` and `xml` will be sorted and aligned first, and the rest tags will be sorted and aligned in the dictionary order.
 
-## Reference
+## References
 
 [Golang AST Visualizer](http://goast.yuroyoro.net/)