change an .is() example

text/* already covers it

lib/request.js

@@ -497,7 +497,7 @@ module.exports = {
    *     // With Content-Type: text/html; charset=utf-8
    *     this.is('html'); // => 'html'
    *     this.is('text/html'); // => 'text/html'
-   *     this.is('text/*', 'text/html'); // => 'text/*'
+   *     this.is('text/*', 'application/json'); // => 'text/*'
    *
    *     // When Content-Type is application/json
    *     this.is('json', 'urlencoded'); // => 'json'