docs(h-grid,toolbar): document toolbar grid prop deprecation

Author: damyanpetev

CHANGELOG.md

@@ -10,7 +10,7 @@ All notable changes for each version of this project will be documented in this
     - Added new property `toggleNodeOnClick` that determines whether clicking over a node will change its expanded state or not. Set to `false` by default.
 - `IgxPivotGrid`
     - `IPivotDimension` interface now exposes a property called `displayName` similar to the one in the `IPivotValue` interface. This property is optional and will be displayed inside the chips for rows and columns in the `IgxPivotGrid`. If the `displayName` property is not set, `memberName` will be used as a fallback.
-- `IgxHierarchicalGrid`
+- `IgxHierarchicalGrid`, `IgxGridToolbar`
     - The declaration of child layout toolbar templates no longer require explicit grid reference so the following:
         ```html
         <igx-row-island>
@@ -21,6 +21,7 @@ All notable changes for each version of this project will be documented in this
         <igx-row-island>
           <igx-grid-toolbar *igxGridToolbar>
         ```
+    - With this change the `grid` property of the `IgxGridToolbar` has been deprecated as it's no longer needed and will be removed in a future version.
 - New directive -  `igxIconButton` directive that provides a way to use an icon as a fully functional button has been added. The new `igxIconButton` comes in three types - flat, outlined and contained (default). All `igxButton`'s with type `icon` will be automatically migrated to the new `igxIconButton`'s with `ng update`.
 - `IgxButton`
     - **Behavioral Change** `buttonSelected` event is now emitted not only when a button gets selected, but also when it gets deselected. However, the event is no longer being emitted on initialization. If this event was used in a scenario where it is assumed that the button gets selected, it's a good idea the logic to be branched now based on `eventArgs.selected` condition.