`LineEditor.onSpecialChar` always triggers `CursorUp`

[benedetto73]

LineEditor.onSpecialChar mistakenly always triggers LineEditorSpecialChar::CursorUp, also when CursorDown is pressed.

Root cause is a simple typo in LineEditor::edit: link

      switch (c) {
        // "ESC [ A" : cursor Up
        case 'A':
          performCursorUp();
          m_state = 0;
          break;

        // "ESC [ B" : cursor Down
        case 'B':
          performCursorUp();
          m_state = 0;
          break;