Return the full Markdown content of a single Bird documentation page, identified by its slug. Slug of the page to read, as returned in the slug field of a docs_search result (e.g. guides/email/contacts). Use index for the documentation landing page. Documentation locale to read, as a language-region code such as en-us. Defaults to en-us when omitted or unavailable. Slug of the page, echoing the requested slug. Documentation locale the page was drawn from. Absolute URL of the page, suitable to cite as the source of an answer. The page's full content as Markdown.