docs: fix typo in jsdoc comment

closes #3430

lib/application.js

@@ -338,7 +338,7 @@ app.param = function param(name, fn) {
  * Assign `setting` to `val`, or return `setting`'s value.
  *
  *    app.set('foo', 'bar');
- *    app.get('foo');
+ *    app.set('foo');
  *    // => "bar"
  *
  * Mounted servers inherit their parent server's settings.