Update src/pages/blog/2024-09-18-codegen.mdx

Co-authored-by: Benjie <[email protected]>

Author: martinbonnin

src/pages/blog/2024-09-18-codegen.mdx

@@ -165,6 +165,6 @@ By using code generation based on operations, you get type safety from your back
 
 All the major code generators ([graphql-code-generator](https://github.com/dotansimha/graphql-code-generator), [Relay](https://relay.dev/), [Apollo iOS](https://github.com/apollographql/apollo-ios), [Apollo Kotlin](https://github.com/apollographql/apollo-kotlin), ...) generate code based on operations.
 
-If you are not already, try them out!
+If you have not already, try them out!
 
 And look out for a new post soon on the improvements we're hoping to bring to GraphQL nullability!