style(docs-infra): fix docs examples for tslint rule semicolon (#38143)

This commit updates the docs examples to be compatible with the
`semicolon` tslint rule.

This is in preparation of updating the docs examples `tslint.json` to
match the one generated for new Angular CLI apps in a future commit.

PR Close #38143

aio/content/examples/hierarchical-dependency-injection/src/app/hero-tax-return.component.ts

@@ -30,9 +30,9 @@ export class HeroTaxReturnComponent {
   onCanceled()  {
     this.flashMessage('Canceled');
     this.heroTaxReturnService.restoreTaxReturn();
-  };
+  }
 
-  onClose() { this.close.emit(); };
+  onClose() { this.close.emit(); }
 
   onSaved() {
     this.flashMessage('Saved');