Modify documentation for view to take into account range special case

[dlfivefifty]

view sometimes does not return a SubArray, e.g.,

julia> view(2:5, 2:3) # returns a range as type is immutable
3:4

This is not really consistent with the docstring for view. So this PR modifies the docstring.

Cf JuliaArrays/FillArrays.jl#84 where we want to do something similar with FillArrays.jl but want to make sure it's justified.

[tkf]

LGTM. I added a suggestion but I don't think that's a hard requirement.

[mcabbott]

Looks like this changed in 1.5, for anyone else wondering. The PR was #26872.

julia> view(1:10, 3:4)
2-element view(::UnitRange{Int64}, 3:4) with eltype Int64:
 3
 4

julia> VERSION
v"1.4.2"

[mbauman]

Ok, I got carried away. I've never been thrilled with defining view() as taking a view.

This is a suggested wholesale reworking of the text; please see what you think.