[Tooltip] Add an example for a light tooltip

[LauraAubin]

Issue summary

I was confusing instances of light colored tooltips with a Popover since it wasn't immediately obvious to me that this prop existed. This PR surfaces that prop via an example in the style guide.

I don't mind if we close this PR if we feel we don't need this addition.

[github-actions]

💦 Potential splash zone of changes introduced to src/**/*.tsx in this pull request:

No significant changes to src/**/*.tsx were detected.

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[LauraAubin]

We might not want this after all. Pending discussion to remove the light prop entirely and default to light instead of dark.

[dleroux]

I'm guessing this one won't be needed?

[LauraAubin]

I'm guessing this one won't be needed?

I closed the PR that would remove the light prop with this reason meaning that this example can still be added.

[kaelig]

Could this include a usage guideline, rather than being a description of what this example does?

[LauraAubin]

For sure! I chatted with @sarahill and @sadiesaurus and we came up with,

Light tooltip draws less attention than the default tooltip. Use only when necessary to provide an explanation for an interface element with less emphasis.

[dleroux]

🐑 🇮🇹 🎩 looks good!