chore(igxForOf): Update Readme and Changelog

Author: dkamburov

CHANGELOG.md

@@ -107,6 +107,13 @@ All notable changes for each version of this project will be documented in this
     @include igx-progress-circular($theme);
     ```
 
+- `IgxForOf`
+    - `IgxForOfTotalItemCount` input is added for the cases when the data is from remote services. This will allow setting the count of the items through the template. And gives the opportunity for the developers to use AsyncPipe for this option:
+    ```html
+    <ng-template igxFor let-item [igxForOf]="data | async" [igxForOfTotalItemCount]="count | async"
+        [igxForContainerSize]="'500px'" [igxForItemSize]="'50px'"></ng-template>
+    ```
+
 ## 8.2.6
 
 ### New Features

projects/igniteui-angular/src/lib/directives/for-of/README.md

@@ -68,6 +68,7 @@ When the contents of the iterator changes, `igxForOf` makes the corresponding ch
 | igxForScrollContainer  | string          | Only the strings `vertical` and `horizontal` are valid and specify the scroll orientation                                  |
 | igxForContainerSize    | string          | The px-affixed size of the container along the axis of scrolling                                                           |
 | igxForScrollContainer  | IgxForOf        | Optionally pass the parent `igxForOf` instance to create a virtual template scrolling both horizontally and vertically     |
+| igxForTotalItemCount   | number          | The total count of the virtual data items, when using remote service. This is exposed to allow setting the count of the items through the template |
 
 ### Outputs