docs(delay): add relevant operator links to delay docs (#6156)

* docs(delay): add relevant operator links to delay docs

should help close #4921

* docs: add throttle; re-order

Co-authored-by: Nicholas Jamieson <nicholas@cartant.com>

src/internal/operators/delay.ts

@@ -41,8 +41,15 @@ import { timer } from '../observable/timer';
  * delayedClicks.subscribe(x => console.log(x));
  * ```
  *
- * @see {@link debounceTime}
  * @see {@link delayWhen}
+ * @see {@link throttle}
+ * @see {@link throttleTime}
+ * @see {@link debounce}
+ * @see {@link debounceTime}
+ * @see {@link sample}
+ * @see {@link sampleTime}
+ * @see {@link audit}
+ * @see {@link auditTime}
  *
  * @param {number|Date} due The delay duration in milliseconds (a `number`) or
  * a `Date` until which the emission of the source items is delayed.