docs(animations): migrate deprecated `@whatItDoes` tag (#23210)

This was not being picked up by the doc-gen as it does not appear to be
part of the public API.

PR Close #23210

packages/animations/src/version.ts

@@ -13,9 +13,9 @@
  */
 
 /**
- * @whatItDoes Represents the version of angular/animations
- *
+ * @description
  *
+ * Represents the version of angular/animations
  */
 export class Version {
   public readonly major: string;