Apply brand tone and writing style fixes

api-playground/openapi-setup.mdx

@@ -183,7 +183,7 @@
 }
 ```
 
 The `x-default` extension supports `apiKey` and `http` bearer security scheme types. The value appears as the default input in the playground's authentication fields. Prefill for security schemes is unconditional and does not require any additional configuration.
 
 Use `x-default` on other schema properties in your OpenAPI specification to set a default value in the API playground without affecting the `default` field in the schema definition. Unlike security schemes, prefill for non-security-scheme properties only takes effect when you set [`api.examples.prefill`](/organize/settings-api) to `true` in your [`docs.json`](/api-playground/overview#example-configuration).
 
@@ -200,7 +200,7 @@
 When enabled, clicking the option downloads your OpenAPI spec directly. Deployments with multiple specs receive them bundled as `api-specs.zip`. On deployments behind `auth` or `userAuth`, only authenticated readers can download the spec.
 
 <Warning>
   The downloaded OpenAPI spec is unfiltered and does not respect [authentication groups](/deploy/authentication-setup). Any authenticated reader who can open the contextual menu receives the full spec, including endpoints and schemas that would otherwise be hidden from their group. Do not enable `download-spec` on an authenticated site if your OpenAPI spec contains endpoints or fields you consider sensitive.
 </Warning>
 
 ## Customize your endpoint pages
@@ -313,7 +313,7 @@
 
 ### Collapse playground fields
 
-Collapse object-type fields in the API playground by default using `x-mint: playground` with `expand: false` on any operation. Request sections like Authorization, Headers, Query, Path, and Body always stay expanded, and the top-level body object stays expanded, but object fields nested within them start collapsed so readers expand only the fields they want to interact with. If `expand` is not set, object fields are expanded by default.
+Collapse object-type fields in the API playground by default using `x-mint: playground` with `expand: false` on any operation. Request sections like Authorization, Headers, Query, Path, and Body always stay expanded, and so does the top-level body object. Object fields nested within them start collapsed, so readers expand only the fields they want to interact with. If `expand` is not set, object fields are expanded by default.
 
 ```json {6-10}
 {