Implement 'do nothing' command handlers for OpenLineAbove and OpenLineBelow for XML doc comments

src/EditorFeatures/Core/Implementation/DocumentationComments/AbstractDocumentationCommentCommandHandler.cs

@@ -21,7 +21,9 @@ namespace Microsoft.CodeAnalysis.Editor.Implementation.DocumentationComments
     internal abstract class AbstractDocumentationCommentCommandHandler<TDocumentationComment, TMemberNode> :
         ICommandHandler<TypeCharCommandArgs>,
         ICommandHandler<ReturnKeyCommandArgs>,
-        ICommandHandler<InsertCommentCommandArgs>
+        ICommandHandler<InsertCommentCommandArgs>,
+        ICommandHandler<OpenLineAboveCommandArgs>,
+        ICommandHandler<OpenLineBelowCommandArgs>
         where TDocumentationComment : SyntaxNode, IStructuredTriviaSyntax
         where TMemberNode : SyntaxNode
     {
@@ -587,5 +589,25 @@ public void ExecuteCommand(InsertCommentCommandArgs args, Action nextHandler)
                     }
                 });
         }
+
+        public CommandState GetCommandState(OpenLineAboveCommandArgs args, Func<CommandState> nextHandler)
+        {
+            return nextHandler();
+        }
+
+        public void ExecuteCommand(OpenLineAboveCommandArgs args, Action nextHandler)
+        {
+            nextHandler();
+        }
+
+        public CommandState GetCommandState(OpenLineBelowCommandArgs args, Func<CommandState> nextHandler)
+        {
+            return nextHandler();
+        }
+
+        public void ExecuteCommand(OpenLineBelowCommandArgs args, Action nextHandler)
+        {
+            nextHandler();
+        }
     }
 }

src/EditorFeatures/Test/DocumentationComments/AbstractDocumentationCommentTests.cs

@@ -71,7 +71,11 @@ protected void VerifyOpenLineAbove(string initialMarkup, string expectedMarkup)
                 var commandHandler = CreateCommandHandler(TestWaitIndicator.Default, undoHistoryRegistry, editorOperationsFactoryService, completionService) as ICommandHandler<OpenLineAboveCommandArgs>;
 
                 var commandArgs = new OpenLineAboveCommandArgs(view, view.TextBuffer);
-                Action nextHandler = delegate { };
+                Action nextHandler = () =>
+                {
+                    var editorOperations = editorOperationsFactoryService.GetEditorOperations(view);
+                    editorOperations.OpenLineAbove();
+                };
 
                 commandHandler.ExecuteCommand(commandArgs, nextHandler);
             });
@@ -84,7 +88,11 @@ protected void VerifyOpenLineBelow(string initialMarkup, string expectedMarkup)
                 var commandHandler = CreateCommandHandler(TestWaitIndicator.Default, undoHistoryRegistry, editorOperationsFactoryService, completionService) as ICommandHandler<OpenLineBelowCommandArgs>;
 
                 var commandArgs = new OpenLineBelowCommandArgs(view, view.TextBuffer);
-                Action nextHandler = delegate { };
+                Action nextHandler = () =>
+                {
+                    var editorOperations = editorOperationsFactoryService.GetEditorOperations(view);
+                    editorOperations.OpenLineBelow();
+                };
 
                 commandHandler.ExecuteCommand(commandArgs, nextHandler);
             });