docs(metadata): Fix usage examples
docs(metadata): Fix usage examples

Author: Benjamin Dopplinger <b.dopplinger@gmail.com>

Closes https://github.com/dart-lang/angular2/pull/262

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=148299176

angulardart/angular,kevmoo/angular,matanlurey/angular,matanlurey/angular,kevmoo/angular,angulardart/angular,chalin/angular2,chalin/angular2,chalin/angular2,kevmoo/angular,angulardart/angular,matanlurey/angular