Add help tooltips on column headers

[NateLanza]

All the plot column headers should show explanatory tooltips when hovered. The # header for Degree currently shows a tooltip when hovered and the rest of the column headers should show tooltips with the same formatting. For deviation: 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/. For attributes, this attribute comes from the imported data. It describes the [items |_] in this intersection where _ is replaced by the items keyword specified in the alttxt sidebar if it has been specified