Improve graph tooltips (#15887

[bramkragten]

Proposed change

Tooltips will not show for all values of the hovered x axis. You dont have to hover the point, but the tooltip of the closest datapoint is show by default.

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New feature (thank you!)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Example configuration

Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to issue or discussion:
• Link to documentation pull request:

Checklist

• The code change is tested and works locally.
• There is no commented out code in this PR.
• Tests have been added to verify that the new code works.

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated for www.home-assistant.io

[piitaya]

Should we use axis: "xy" to only select one chart at a time?

interaction: {
  mode: "nearest",
  axis: "xy",
  intersect: false,
},

[bramkragten]

I don't think that is what we want? Especially if the y values are close it gets really hard then?