fix(router): fix malformed jsdoc comment for RouterLinkWithHref export

The export statement was incorrectly placed inside the JSDoc comment block,
and there was a stray text fragment "nstead." from the deprecation message.
This moves the export statement outside the comment and removes the stray text.

packages/router/src/directives/router_link.ts

@@ -587,8 +587,6 @@ export class RouterLink implements OnChanges, OnDestroy {
  * An alias for the `RouterLink` directive.
  * Deprecated since v15, use `RouterLink` directive instead.
  *
-export { RouterLink as RouterLinkWithHref };
-nstead.
  * @publicApi
  */
 export {RouterLink as RouterLinkWithHref};