Update valid-snake-case.md

Author: milwad-dev

docs/1.x/valid-snake-case.md

@@ -1,6 +1,6 @@
 ## ValidSnakeCase
 
-If you want to validate snake-case string, you can use `ValidSnakeCase` rule:
+If you want to validate the snake-case string, you can use the `ValidSnakeCase` rule:
 
 ```php
 use Milwad\LaravelValidate\Rules\ValidSnakeCase;