Unexpected result for `diff` over DateTime range

General Usage
1

Consider the following:

julia> range = Dates.DateTime(2019):Dates.Year(1):Dates.DateTime(2020)
Dates.DateTime("2019-01-01T00:00:00"):Dates.Year(1):Dates.DateTime("2020-01-01T00:00:00")

julia> diff(range)
1-element Vector{Dates.DateTime}:
 0001-12-31T00:00:00

julia> diff(collect(range))
1-element Vector{Dates.Millisecond}:
 31536000000 milliseconds

The output for diff(::AbstractRange) seems wrong in this case.

2

Please use the latest Julia version (1.8.0)

julia> a = Dates.DateTime("2019-01-01T00:00:00"):Dates.Year(1):Dates.DateTime("2020-01-01T00:00:00")
DateTime("2019-01-01T00:00:00"):Year(1):DateTime("2020-01-01T00:00:00")

julia> diff(a)
1-element Vector{Millisecond}:
 31536000000 milliseconds