Change message when redirect mode set to error

The original error message does not provide enough information about
what went wrong. It simply states a configuration setting.

Via: node-fetch/node-fetch#653

lib/index.js

@@ -116,7 +116,7 @@ const fetch = (url, opts) => {
         // HTTP fetch step 5.5
         switch (request.redirect) {
           case 'error':
-            reject(new FetchError(`redirect mode is set to error: ${
+            reject(new FetchError(`uri requested responds with a redirect, redirect mode is set to error: ${
               request.url}`, 'no-redirect'))
             finalize()
             return