feat(python): Add tooltip by default to charts

[MarcoGorelli]

I think this is quite nice as the plot is then more interactive by default (and something Altair might want to do anyway? vega/altair#3394)

cc @joelostblom fancy taking a look? does this make sense?

Demo (the tooltip appears where I had my pointer):

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Separate PR incoming to improve docs

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 79.90%. Comparing base (aa3b2c3) to head (d15c672).
Report is 27 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #18625      +/-   ##
==========================================
- Coverage   79.94%   79.90%   -0.05%     
==========================================
  Files        1505     1506       +1     
  Lines      202579   203219     +640     
  Branches     2873     2887      +14     
==========================================
+ Hits       161958   162383     +425     
- Misses      40073    40289     +216     
+ Partials      548      547       -1     

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[dangotbanned]

Just linking the context for this change #18609 (comment)

cc'ing @mattijn as this is a possible solution for vega/altair#3582 (comment)

[MarcoGorelli]

note that this is a backwards-compatible change, as anyone passing tooltip will still have their code work due to **kwargs

[joelostblom]

I think tooltips by default is convenient and the approach here seems to make sense to me. Just one minor comment.

[joelostblom]

Are marks guaranteed to be strings here? It seems like they are by default in polars, but I'm flagging just in case you want to do something like this to check that the mark is not a dict (which you might already have seen).

[dangotbanned]

@joelostblom I'm pretty sure @MarcoGorelli has been peeking at that PR 😉

Maybe I'm being overly cautious here, but I'm not sure we've tested this thoroughly enough for it to be included in polars without any tests yet

[MarcoGorelli]

thanks both!

I've reworked this to create tooltip= explicitly, reckon this is more robust / robust-enough?

[joelostblom]

Looks good to me too

[dangotbanned]

thanks both!

I've reworked this to create tooltip= explicitly, reckon this is more robust / robust-enough?

Yeah this is great d15c672 (#18625)

Thanks @MarcoGorelli

[AdrienDart]

Hi, this is causing issues on my side with Schema validation error: try using df.plot.line(x=alt.X("date", axis=alt.Axis(labelAngle=-90), y='price', color='stock')