Update Nested_crud.md (#179)

Fixed typo ("Fist of" -> "First off,")

Author: maximilien-noal

docs/blazor_server/Nested_crud.md

@@ -9,7 +9,7 @@ And these subgrids can also be configured with CRUD support, so you can add, edi
 
 ### Column definition
 
-Fist of all the column definition of the main grid must include the ```SubGrid``` method for those columns that have a 1:N relationship. 
+First off, all the column definition of the main grid must include the ```SubGrid``` method for those columns that have a 1:N relationship. 
 
 ```c#
     c.Add(o => o.OrderDetails).Titled("Order Details").SubGrid(subgrid, ("OrderID", "OrderID"));
@@ -56,4 +56,4 @@ Then you have to define the subgrid that you want to show on the CRUD forms.
 ```
 This function is passed as parameter of the ```Subgrid``` method used on the first step. Of course subgrids must be configured with CRUD support using the ```Crud()``` method of the ```GridClient``` object.
 
-[<- CRUD](Crud.md) | [Events, exceptions and CRUD validation ->](Events.md)
+[<- CRUD](Crud.md) | [Events, exceptions and CRUD validation ->](Events.md)