docs: Expand plotting docs

[MarcoGorelli]

In summary, this:

• shows a few more common configuration options in the visualisation guide (axis labels, title)
• links to Altair's configuration docs
• add tips for some common configuration tasks (label rotation, opacity, width / height / title)

---

screenshots of how it looks (current user guide for comparison https://docs.pola.rs/user-guide/misc/visualization/)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 79.62%. Comparing base (dc54699) to head (47aca4f).
Report is 23 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #19719      +/-   ##
==========================================
- Coverage   79.63%   79.62%   -0.01%     
==========================================
  Files        1564     1564              
  Lines      217478   217478              
  Branches     2473     2473              
==========================================
- Hits       173181   173177       -4     
- Misses      43728    43732       +4     
  Partials      569      569              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[MarcoGorelli]

@rodrigogiraoserrao fancy taking a look?

[rodrigogiraoserrao]

I only have a comment: it feels like there was something missing in a docstring.
If I misinterpreted it, just let me know and I'll change my review status.

Sorry I missed the PR!

[rodrigogiraoserrao]

This last bullet point feels incomplete:
Set the x-axis title by passing x=alt.X(...) instead of x=...... where? Where do I pass it?

(Also, you have the same list in visualization.md and in series.py but this fourth item is only present in this list. It looks like all three lists should look the same but I'm not sure, so I'm just flagging this here in case you missed it.)

[BartSchuurmans]

This documentation is exactly what I needed!

I noticed that some of the examples of the different libraries have the x/y axes swapped; might be nice to make that consistent.

[MarcoGorelli]

good points, thanks both for your reviews! have addressed

[rodrigogiraoserrao]

Looks good to me :D

[MarcoGorelli]

awesome, thanks!