add fancy error

Signed-off-by: peter szemraj <peterszemraj@gmail.com>

app.py

@@ -79,7 +79,13 @@ def convert_PDF(
     file_path = Path(pdf_obj.name)
     if not file_path.suffix == ".pdf":
         logging.error(f"File {file_path} is not a PDF file")
-        return "File is not a PDF file", None, None
+
+        html_error = f"""
+        <div style="color: red; font-size: 20px; font-weight: bold;">
+        File {file_path} is not a PDF file
+        </div>
+        """
+        return "File is not a PDF file", html_error, None
     conversion_stats = convert_PDF_to_Text(
         file_path,
         ocr_model=ocr_model,