`union` example in doc is wrong

[arnaudh]

From the docs:

julia> union([1..10], [5..15])
1-element Vector{Interval{Int64, Closed, Closed}}:
 Interval{Int64, Closed, Closed}(1, 15)

However when I run this:

julia> union([1..10], [5..15])
2-element Vector{Interval{Int64, Closed, Closed}}:
 Interval{Int64, Closed, Closed}(1, 10)
 Interval{Int64, Closed, Closed}(5, 15)

• Intervals v1.8.0
• Julia 1.6.1