message: Fix error of `dd` when `startofline` is false
  Fixes
diff: @@ -299,8 +299,8 @@ export class Position extends vscode.Position {
  resultChar = this.character + diff.character;
  } else if (diff.type === PositionDiffType.ExactCharacter) {
  resultChar = diff.character;
  - } else if (diff.type === PositionDiffType.ObeyStartOfLine && configuration.startofline) {
  - resultChar = new Position(resultLine, 0).obeyStartOfLine().character;
  + } else if (diff.type === PositionDiffType.ObeyStartOfLine) {
  + resultChar = this.withLine(resultLine).obeyStartOfLine().character;
  } else {
  throw new Error(`Unknown PositionDiffType: ${diff.type}`);
  }
  