fix(core): fix docs for output migration (angular#60764)

missing EventEmitter import

PR Close angular#60764

Author: aparzi

adev/src/content/reference/migrations/outputs.md

@@ -22,7 +22,7 @@ ng generate @angular/core:output-migration
 **Before**
 
 ```typescript
-import {Component, Output} from '@angular/core';
+import {Component, Output, EventEmitter} from '@angular/core';
 
 @Component({
   template: `<button (click)="someMethod('test')">emit</button>`