⚡️(frontend) inject language attribute to pdf export

added language="fr-FR" to <Document /> in ModalExport.tsx via cloneElement()
to improve accessibility and ensure correct screen reader pronunciation

Signed-off-by: Cyril <c.gromoff@gmail.com>

src/frontend/apps/impress/src/features/docs/doc-export/components/ModalExport.tsx

@@ -10,7 +10,8 @@ import {
   useToastProvider,
 } from '@openfun/cunningham-react';
 import { DocumentProps, pdf } from '@react-pdf/renderer';
-import { useMemo, useState } from 'react';
+import i18next from 'i18next';
+import { cloneElement, isValidElement, useMemo, useState } from 'react';
 import { useTranslation } from 'react-i18next';
 import { css } from 'styled-components';
 
@@ -92,10 +93,15 @@ export const ModalExport = ({ onClose, doc }: ModalExportProps) => {
       const exporter = new PDFExporter(editor.schema, pdfDocsSchemaMappings, {
         resolveFileUrl: async (url) => exportCorsResolveFileUrl(doc.id, url),
       });
-      const pdfDocument = (await exporter.toReactPDFDocument(
+      const rawPdfDocument = (await exporter.toReactPDFDocument(
         exportDocument,
       )) as React.ReactElement<DocumentProps>;
 
+      // Inject language for screen reader support
+      const pdfDocument = isValidElement(rawPdfDocument)
+        ? cloneElement(rawPdfDocument, { language: i18next.language })
+        : rawPdfDocument;
+
       blobExport = await pdf(pdfDocument).toBlob();
     } else {
       const exporter = new DOCXExporter(editor.schema, docxDocsSchemaMappings, {