Update valid-vatid.md

Author: milwad-dev

docs/1.x/valid-vatid.md

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