Added Error List icon support

Author: madskristensen

src/toolkit/Community.VisualStudio.Toolkit.Shared/ErrorList/ErrorListItem.cs

@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using Microsoft.VisualStudio.Imaging.Interop;
 using Microsoft.VisualStudio.Shell.Interop;
 
 namespace Community.VisualStudio.Toolkit
@@ -63,6 +64,11 @@ public class ErrorListItem
         /// </summary>
         public string? BuildTool { get; set; }
 
+        /// <summary>
+        /// The image icon moniker to use for the error list item.
+        /// </summary>
+        public ImageMoniker Icon { get; set; }
+
         /// <inheritdoc/>
         public override bool Equals(object obj)
         {

src/toolkit/Community.VisualStudio.Toolkit.Shared/ErrorList/TableEntriesSnapshot.cs

@@ -85,6 +85,11 @@ public override bool TryGetValue(int index, string columnName, out object? conte
                     content = _errors[index].ErrorCodeToolTip;
                     break;
 
+                case StandardTableKeyNames.PriorityImage:
+                case StandardTableKeyNames.ErrorSeverityImage:
+                    content = _errors[index].Icon;
+                    break;
+
                 default:
                     content = null;
                     return false;