Fixed unclear wording in the validation section (#1096)

* Fixed unclear wording in the validation section

* Update spec/Section 5 -- Validation.md

* Update Section 5 -- Validation.md

shorten further

---------

Co-authored-by: Benjie <benjie@jemjie.com>
Co-authored-by: Lee Byron <lee@leebyron.com>

Author: 3 people

spec/Section 5 -- Validation.md

@@ -32,8 +32,7 @@ free of any validation errors, and have not changed since.
 
 **Examples**
 
-For this section of this schema, we will assume the following type system in
-order to demonstrate examples:
+The examples in this section will use the following types:
 
 ```graphql example
 type Query {