removed warnings

Annotations.cs

@@ -21,6 +21,7 @@ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE. */
 
 using System;
+
 // ReSharper disable InheritdocConsiderUsage
 
 #pragma warning disable 1591
@@ -31,7 +32,7 @@ using System;
 // ReSharper disable MemberCanBeProtected.Global
 // ReSharper disable InconsistentNaming
 
-namespace ModernWpfPlayground.Annotations
+namespace ModernWpfPlayground
 {
   /// <summary>
   /// Indicates that the value of the marked element could be <c>null</c> sometimes,