Steepest Climb

A café owner looks at a line chart of visitors per day. She wants to know where the line climbs most steeply from one point to the next.

Task: write steepest_climb(days, visitors). days holds the day names in order, and visitors[i] is the count for days[i].

Return a list of two day names, [from_day, to_day], for the pair of neighbouring days with the biggest rise in visitors.

• Only compare each day with the day right after it.
• If two climbs tie for biggest, return the earlier one.
• If the line never rises (it only falls or stays flat), or there are fewer than two days, return [].