fix(seo): identify sponsored links

[caugner]

Summary

(MP-1161)

Problem

We don't identify our placement links as sponsored, but Google recommends this.

Solution

Update the rel attribute of those links to include sponsored.

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Screenshots

(No visible change.)

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How did you test this change?

Trivial change, not explicitly tested.

[fiji-flo]

I'd say it's a feature not a fix :)

[caugner]

I'd say it's a feature not a fix :)

I guess you could say it's a feat(placement) or a fix(seo) (hopefully), but overall I don't think it's that big of a change to warrant feat:.