Fixes

Server selection for slotted servers was not changing the request URL
Copy button in Headers is now disabled if there are no headers
Response headers are hidden until deliberately shown
Response body was not being formatted
Response body was not being rendered with error responses
Re-add CSS variable to style form titles in request panel, and fix indenting in the titles

Features

For required fields that have no other restrictions, do not show as invalid. Instead, show an info message under the field
Added noOverview property to remove Overview items from navigation. If enabled, clicking on the endpoint name will select it, and the arrow will toggle the collapsible element
Added operationsOpened property to toggle all operations opened/closed
Added credentialsSource to optionally populate credentials in the request editor