Test if on pair with st.markdown

[arnaudmiribel]

Let's try and see if we can get tests from streamlit/streamlit on the Markdown part to see if mdlit() covers most cases successfully too. We can also choose it's ok if it doesn't, since using both as complementary solutions isn't that bad, too.

[arnaudmiribel]

https://github.com/streamlit/streamlit/blob/9201a1980301a0cd62a5937982c410df08847a2f/lib/tests/streamlit/write_test.py

https://github.com/streamlit/streamlit/blob/6e7c08b9eea49d16f05e2e7b245a61395506f8ef/lib/tests/streamlit/streamlit_test.py#L498

[arnaudmiribel]

StreamlitMarkdown definition from react-markdown here: https://github.com/streamlit/streamlit/blob/7550b6e2edfdc2c3a11fd6b68d8e64541963237a/frontend/src/components/shared/StreamlitMarkdown/StreamlitMarkdown.tsx