Since #12241 we have notifications for this when the user navigates away from the viewer, but we do not yet warn when switching documents, which means that if you call e.g. `PDFViewerApplication.open` with a new document (or directly call `BaseViewer.setDocument` when using the viewer components standalone) there won't be any warning about losing form data. This should be addressed.
case 74: 
      case 78: 
        turnPage = 1;
        break;
      case 36: 
        if (isViewerInPresentationMode || PDFViewerApplication.page > 1) {
          PDFViewerApplication.page = 1;
          handled = true;
          ensureViewerFocused = true;
        }
        break;
      case 35: 
        if (
          isViewerInPresentationMode ||
          PDFViewerApplication.page < PDFViewerApplication.pagesCount
        ) {
          PDFViewerApplication.page = PDFViewerApplication.pagesCount;
          handled = true;
          ensureViewerFocused = true;
        }
        break;
      case 83: 
        PDFViewerApplication.pdfCursorTools.switchTool(CursorTool.SELECT);
        break;
      case 72: 
        PDFViewerApplication.pdfCursorTools.switchTool(CursorTool.HAND);
        break;
      case 82: 
        PDFViewerApplication.rotatePages(90);