docs(table): make viewchange documentation private (#15068)

src/cdk/table/table.ts

@@ -357,6 +357,8 @@ export class CdkTable<T> implements AfterContentChecked, CollectionViewer, OnDes
   /**
    * Stream containing the latest information on what rows are being displayed on screen.
    * Can be used by the data source to as a heuristic of what data should be provided.
+   *
+   * @docs-private
    */
   viewChange: BehaviorSubject<{start: number, end: number}> =
       new BehaviorSubject<{start: number, end: number}>({start: 0, end: Number.MAX_VALUE});