message: fix(aio): markdown typo in Tour of Heroes tutorial
  PR Close
diff: @@ -44,7 +44,7 @@ the class with the `@Injectable()` decorator.
  The `@Injectable()` decorator tells Angular that this service _might_ itself
  have injected dependencies.
  -It doesn't have dependencies now but [it will soon](#inject-message-service}.
  +It doesn't have dependencies now but [it will soon](#inject-message-service).
  Whether it does or it doesn't, it's good practice to keep the decorator.
  <div class="l-sub-section">
  