Docs: unconditionally show plain Python example

[tobiasdiez]

Removes the toggle to disable the "Python" tab in the documentation (so that tab is now always displayed). Should fix the issue mentioned in https://groups.google.com/g/sage-release/c/x5zO6z5c0d4/m/CougOT6mBgAJ.

📝 Checklist

• The title is concise and informative.
• The description explains in detail what this PR is about.
• I have linked a relevant issue or discussion.
• I have created tests covering the changes.
• I have updated the documentation and checked the documentation preview.

⌛ Dependencies

[github-actions]

Documentation preview for this PR (built with commit 85cec95; changes) is ready! 🎉
This preview will update shortly after each push to this PR.

[dimpase]

it's not clear from the description how the real problem - a missing sphinx dependency - is tackled.

[tobiasdiez]

it's not clear from the description how the real problem - a missing sphinx dependency - is tackled.

jupyter_sphinx is required if you build the "live doc"

sage/src/sage_docbuild/conf.py

Lines 64 to 65 in 85cec95

	if SAGE_LIVE_DOC == 'yes':
	JupyterSphinx().require()

if you don't build the live doc, then it's not required and the following code makes the doc build in this case:
https://github.com/sagemath/sage/pull/41142/files#diff-44710db7069c4a9b817b5603e38fa2153c59357baf4c66f51e6f123e54e835fcR1087-R1090

What still doesn't work is --disable-notebook and activating live docs, but that never worked before and would indeed require the changes to sage-the-distro that you mentioned on the mailing list.

The "bug" that I've introduced in #39030 was to incorporate the no-preparsed-examples toggle in the if check.