what nickname is given to inhabitants of Wiltshire

Moonrakers. According to legend, some inhabitants of the county were so "rustic" that - when they saw the reflection of the moon in a pond - they tried to rake it out.

That’s not the way us “rustics” tell the story …
A gang of smugglers hid some barrels of brandy in a pond one night. Once they were safely away, their confederates started to haul them out with rakes. Along came the customs men, who – naturally – asked what they were doing raking a pond at that time of night. One pointed at the moon’s reflection, saying that they were going to get that big round of cheese out of the water. Off went the customs men, shaking their heads in pity, leaving the smugglers to get on with the job.
Former native of Wiltshire – us’m not uz ztoopid uz we zound!

My outline of the source-story was the one which first appeared in print in 1787, according to The Oxford English Dictionary. The dictionary goes on to say: "In Wiltshire, a more complimentary turn is given to the story"...namely, the one you offer, JoMs. Us non-Wiltshire folk will just have to decide which one to believe!