Fix markdown cell marker formatting for export to Python (microsoft#14360)

Author: joyceerhl

news/2 Fixes/14359.md

@@ -0,0 +1 @@
+Fix markdown cell marker when exporting a notebook to a Python script.

src/client/datascience/jupyter/jupyterImporter.ts

@@ -36,7 +36,7 @@ export class JupyterImporter implements INotebookImporter {
 {% endblock codecell %}
 {% block in_prompt %}{% endblock in_prompt %}
 {% block input %}{{ cell.source | ipython2python }}{% endblock input %}
-{% block markdowncell scoped %}{0} [markdown]
+{% block markdowncell scoped %}{1} [markdown]
 {{ cell.source | comment_lines }}
 {% endblock markdowncell %}`;
     private readonly nbconvert5Null = 'null.tpl';

src/test/datascience/notebook.functional.test.ts

@@ -676,6 +676,7 @@ suite('DataScience notebook tests', () => {
 
                     // Make sure we have a cell in our results
                     assert.ok(/#\s*%%/.test(results), 'No cells in returned import');
+                    assert.ok(!results.includes('tpl'), 'Formatted template with wrong arguments');
                 } finally {
                     try {
                         importer.dispose();