import { WrappedRequest } from "https://deno.land/x/opine@2.2.0/src/request.ts";
Return request header.
The Referrer header field is special-cased,
both Referrer and Referer are interchangeable.
Examples:
req.get('Content-Type');
// => "text/plain"
req.get('content-type');
// => "text/plain"
req.get('Something');
// => undefined
Aliased as req.header().