HTML exporter DeprecationWarning: 'jinja2.Markup' is deprecated and will be removed in Jinja 3.1

[sjdemartini]

When using the HTML exporter, the following warning will show up:

   /.../venv/lib/python3.8/site-packages/nbconvert/exporters/html.py:125: DeprecationWarning: 'jinja2.Markup' is deprecated and will be removed in Jinja 3.1. Import 'markupsafe.Markup' instead.
     return jinja2.Markup(code)

This was updated in jinja2 here pallets/jinja#1391. Semi-related to #1568 (another Jinja deprecation warning).

jinja2.Markup is used in a few places in the HTML exporter:

nbconvert/nbconvert/exporters/html.py

Line 135 in 90b3911

return jinja2.Markup(code)

nbconvert/nbconvert/exporters/html.py

Line 140 in 90b3911

return jinja2.Markup(code)

nbconvert/nbconvert/exporters/html.py

Line 165 in 90b3911

return jinja2.Markup(src)

It seems it needs to be replaced with an import from the markupsafe package instead of jinja2.

Nbconvert version: 6.0.7 (deprecated class usage appears to be present on master as shown above, so will presumably show up with 6.1.0 as well)

[minrk]

closed by #1737