docs: Document aggregate FieldType (#624)

Co-authored-by: Dimo Dimov <[email protected]>

Author: dimodi

components/grid/grouping/aggregates.md

@@ -47,13 +47,13 @@ You can use aggregates in the following templates:
 To enable aggregates:
 
 1. Under the `GridAggregates` tag, define the `GridAggregate` entries to enable the aggregations per field you want to use.
+1. If the Grid is bound to a dynamic object, set the `FieldType` attribute of the `GridAggregate` tag (it is of type `Type`).
 1. Use the aggregate result in the templates that support it - their `context` is strongly typed and carries the aggregate values in the respective fields.
 1. Set the grid's `Groupable` property to `true`.
     * If you will be using only `FooterTemplate`s - grouping is not required.
 1. Group the grid to see the effect on group-specific templates
 
 
-
 ## Example
 
 >caption Use Aggregates in the Telerik Blazor Grid

components/treelist/aggregates.md

@@ -31,6 +31,7 @@ To enable aggregates:
 
 1. Set the grid's `Groupable` property to `true`.
 1. Under the `GridAggregates` tag, define the `GridAggregate` entries to enable the aggregations per field you want to use.
+1. If the TreeList is bound to a dynamic object, set the `FieldType` attribute of the `GridAggregate` tag (it is of type `Type`).
 1. Use the aggregate result in the templates that support it - their `context` is strongly typed and carries the aggregate values in the respective fields.
 1. Group the grid to see the effect