add missing UndoGroups for CommentRegion and IndentSelection commands

src/Main/Base/Project/Src/Editor/Commands/CommentRegion.cs

@@ -23,7 +23,8 @@ namespace ICSharpCode.SharpDevelop.Editor.Commands
 			if (provider == null)
 				return;
 			
-			provider.TextEditor.Language.FormattingStrategy.SurroundSelectionWithComment(provider.TextEditor);
+			using (provider.TextEditor.Document.OpenUndoGroup())
+				provider.TextEditor.Language.FormattingStrategy.SurroundSelectionWithComment(provider.TextEditor);
 		}
 	}
 }

src/Main/Base/Project/Src/Editor/Commands/IndentSelection.cs

@@ -33,7 +33,8 @@ namespace ICSharpCode.SharpDevelop.Editor.Commands
 				endLine = provider.TextEditor.Document.GetLineForOffset(provider.TextEditor.SelectionStart + provider.TextEditor.SelectionLength).LineNumber;
 			}
 			
-			provider.TextEditor.Language.FormattingStrategy.IndentLines(provider.TextEditor, beginLine, endLine);
+			using (provider.TextEditor.Document.OpenUndoGroup())
+				provider.TextEditor.Language.FormattingStrategy.IndentLines(provider.TextEditor, beginLine, endLine);
 		}
 	}
 }