typo: Acitivity -> Activity (dotnet#2154)

Author: nschonni

xml/System.Activities.Presentation.Metadata/MetadataStore.xml

@@ -24,7 +24,7 @@
    
   
 ## Examples  
- The following code example shows how to associate the `AcitivityDesigner1` custom activity designer with a custom activity. For more information about how to create custom activity designers, see [How to: Create a Custom Activity Designer](~/docs/framework/windows-workflow-foundation/how-to-create-a-custom-activity-designer.md).  
+ The following code example shows how to associate the `ActivityDesigner1` custom activity designer with a custom activity. For more information about how to create custom activity designers, see [How to: Create a Custom Activity Designer](~/docs/framework/windows-workflow-foundation/how-to-create-a-custom-activity-designer.md).  
   
 ```csharp  
 internal class Metadata : IRegisterMetadata