Add better help tooltips to column headers

[NateLanza]

Does this PR close any open issues?

Closes #339

Give a longer description of what this PR addresses and why it's needed

• Changes Size header tooltip from nothing to "Size (cardinality)"
• Changes Degree (#) header tooltip from "Degree" to "Number of intersecting sets"
• Changes Deviation header tooltip from "Deviation" to "Measure for how "surprising" the size of an intersection is. This also considers the size of the sets. For more information visit https://upset.app/advanced/"

Have you added or updated relevant tests?

• Yes
• No changes are needed

Have you added or updated relevant documentation?

• Yes
• No changes are needed

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