Fix missing "s" on components.schemas OpenAPI doc section (#1630)

it's components.schemas, not components.schema: https://swagger.io/specification/#components-object

Author: lawreka

api-playground/openapi-setup.mdx

@@ -489,7 +489,7 @@ The scraper generates:
 
 ### Create `MDX` files for OpenAPI schemas
 
-You can create individual pages for any OpenAPI schema defined in an OpenAPI document's `components.schema` field:
+You can create individual pages for any OpenAPI schema defined in an OpenAPI document's `components.schemas` field:
 
 <CodeGroup>