Prune "50,000" from Contrib. Limits

[seemantk]

On the opening question of the section, there are no (longer) grids or states with 50,000 limit.

Pruning it would

• improve the UX (ie, nothing happens on hover == uh oh, is it broken?)
• give back a line to smaller displays ;)

[curran]

This is a great idea.

I wonder what the best approach would be. Two ideas come to mind:

• Define two separate legend entries, one with the 50,000 and one without
• Modify the pruning logic to dynamically remove bins on the top that don't have any entries (data-driven)