Parametrized messages.

Author: kannansuresh

src/Aneejian.PowerPoint.Downsizer/Constants.Messages.cs

@@ -5,6 +5,10 @@ public static partial class Constants
         public static class Messages
         {
             public const string NothingToRemove = "Nothing to remove. All layouts and master slides in use.";
+
+            public const string SlideMasterDonwsizeSuccess = "Successfully removed unused custom layouts and master slides.";
+
+            public const string SlideMasterDonwsizeFailed = "Failed to remove unused custom layouts and master slides.";
         }
     }
 }

src/Aneejian.PowerPoint.Downsizer/SlideMaster/Downsizer.cs

@@ -27,12 +27,12 @@ public async Task<IDownsizeResponse> Downsize(IDownsizePotential potential, IDow
                 }
 
                 downsizeResponse.IsSuccess = true;
-                downsizeResponse.ResultMessage = "Successfully removed unused custom layouts and master slides.";
+                downsizeResponse.ResultMessage = Constants.Messages.SlideMasterDonwsizeSuccess;
             }
             catch (Exception e)
             {
                 downsizeResponse.Exception = e;
-                downsizeResponse.ResultMessage = "Failed to remove unused custom layouts and master slides.";
+                downsizeResponse.ResultMessage = Constants.Messages.SlideMasterDonwsizeFailed;
             }
 
             updateStat?.Invoke(downsizeResponse);