Grapher data tables should make the Other section easier to find

[samizdatco]

Core problem

Many data tables contain a mixture of country and non-country rows. Currently these are sorted separately into a Countries section at the top and an Other section that appears when you scroll past the final country row:

The problem is that it's unclear from the default view of the table that this Other section even exists and there is no easy way to jump directly to it (whereas scrolling to the first country is trivial since it's at the topmost scroll position).

Proposed solution

The Other row could be positioned as a sticky footer that is initially stuck to the bottom of the tableview until it is scrolled into view, then sticks to the top when it's scrolled off the top:

Clicking on the Other label will scroll the table so the first row in that section is at the top

Trade Offs

Adding a constantly present Other row means one fewer row of actual data will be visible at any given time. Unless we also add a sticky Countries row that's positioned above the first row, there won't be a comparable one-click way to jump back to the top, but flick-scrolling makes this less challenging to accomplish in the first place (so it's probably not worth sacrificing another row for).