chore(grid): add info to README files #5460

Author: hanastasov

README.md

@@ -43,7 +43,7 @@ You can find source files under the [`src`](https://github.com/IgniteUI/igniteui
 |input group|Available|[Readme](https://github.com/IgniteUI/igniteui-angular/blob/master/projects/igniteui-angular/src/lib/input-group/README.md)|[Docs](https://www.infragistics.com/products/ignite-ui-angular/angular/components/input_group.html)|Animations|Available|[Readme](https://github.com/IgniteUI/igniteui-angular/blob/master/projects/igniteui-angular/src/lib/animations/README.md)||
 |linear progress|Available|[Readme](https://github.com/IgniteUI/igniteui-angular/tree/master/projects/igniteui-angular/src/lib/progressbar)|[Docs](https://www.infragistics.com/products/ignite-ui-angular/angular/components/linear_progress.html)|dataUtil|Available|[Readme](https://github.com/IgniteUI/igniteui-angular/blob/master/projects/igniteui-angular/src/lib/data-operations/README-DATAUTIL.md)||
 |list|Available|[Readme](https://github.com/IgniteUI/igniteui-angular/blob/master/projects/igniteui-angular/src/lib/list/README.md)|[Docs](https://www.infragistics.com/products/ignite-ui-angular/angular/components/list.html)|dataContainer|Available|[Readme](https://github.com/IgniteUI/igniteui-angular/blob/master/projects/igniteui-angular/src/lib/data-operations/README-DATACONTAINER.md)||
-|month picker|Available|[Readme](https://github.com/IgniteUI/igniteui-angular/blob/master/projects/igniteui-angular/src/lib/calendar/month-picker/README.md)|[Docs](https://www.infragistics.com/products/ignite-ui-angular/angular/components/month_picker.html)|||||
+|month picker|Available|[Readme](https://github.com/IgniteUI/igniteui-angular/blob/master/projects/igniteui-angular/src/lib/calendar/month-picker/README.md)|[Docs](https://www.infragistics.com/products/ignite-ui-angular/angular/components/month_picker.html)|IgxGridState|Available|[Readme](https://github.com/IgniteUI/igniteui-angular/blob/master/projects/igniteui-angular/src/lib/grids/README.md)|[Docs](https://www.infragistics.com/products/ignite-ui-angular/angular/components/grid/state_persistence.html)||
 |navbar|Available|[Readme](https://github.com/IgniteUI/igniteui-angular/blob/master/projects/igniteui-angular/src/lib/navbar/README.md)|[Docs](https://www.infragistics.com/products/ignite-ui-angular/angular/components/navbar.html)|||||
 |navigation drawer|Available|[Readme](https://github.com/IgniteUI/igniteui-angular/blob/master/projects/igniteui-angular/src/lib/navigation-drawer/README.md)|[Docs](https://www.infragistics.com/products/ignite-ui-angular/angular/components/navdrawer.html)|||||
 |radio|Available|[Readme](https://github.com/IgniteUI/igniteui-angular/blob/master/projects/igniteui-angular/src/lib/radio/README.md)|[Docs](https://www.infragistics.com/products/ignite-ui-angular/angular/components/radio_button.html)|||||

projects/igniteui-angular/src/lib/grids/README.md

@@ -494,3 +494,18 @@ import {
 |Name|Return Type|Description|
 |--- |--- |--- |
 |`update(val: any)`|void|Emits the `onEditDone` event and updates the appropriate record in the data source.|
+
+## IgxGridState Directive
+
+### Getters/Setters
+
+|Name|Type|Getter|Setter|Description|
+|--- |--- |--- |--- |--- |
+|`options`|IGridStateOptions|Yes|Yes|Features to be exluded from tracking in the IgxGridState directive.|
+
+### Methods
+
+|Name|Return Type|Description|
+|--- |--- |--- |
+|`getState(serialize: boolean, feature?: string | string[])`|IGridState, string|Gets the state of a feature or states of all grid features, unless a certain feature is disabled through the `options` property..|
+|`setState(val: IGridState | string)`|void|Restores grid features' state based on the IGridState object passed as an argument.|