Fix punctuation

docs/source/testing/test-mocks.mdx

@@ -6,7 +6,7 @@ When unit testing code that uses your generated operation models, you will often
 
 ## Purpose
 
-Generated test mocks provide a type-safe way to mock your response models. Rather than dealing with cumbersome and error prone JSON data, test mocks make mocking safer,more concise, and reusable. They are mutable, offer code completion in Xcode, and update with new fields automatically as your schema and operations change.
+Generated test mocks provide a type-safe way to mock your response models. Rather than dealing with cumbersome and error prone JSON data, test mocks make mocking safer, more concise, and reusable. They are mutable, offer code completion in Xcode, and update with new fields automatically as your schema and operations change.
 
 ### Mocking GraphQL responses with JSON