reorder pmap arguments to allow do-block syntax

[mweastwood]

This fixes #26684

Now you can do something like:

julia> using Distributed

julia> addprocs(4)
4-element Array{Int64,1}:
 2
 3
 4
 5

julia> pmap(WorkerPool([2, 3, 4]), 1:10) do x
           myid()
       end
10-element Array{Int64,1}:
 2
 3
 4
 3
 2
 4
 3
 2
 4
 3

I wasn't entirely sure where I should put the deprecations, so I put them near the pmap definition, but happy to move them if there's a better location.

[ararslan]

These should go in base/deprecated.jl near the bottom with a reference to the issue this closes. Other entries in that file should provide a decent example.

[mweastwood]

I guess I was confused because this is an stdlib package. Do those deprecations still live in base/deprecated.jl?

[ararslan]

Oh you're absolutely right, sorry about that, I had forgotten that pmap moved to the stdlib. In that case it looks like other Distributed deprecations are done in stdlib/Distributed/src/Distributed.jl near the bottom.

[mweastwood]

No worries! Just pushed another commit that moves them to Distributed.jl

[ararslan]

Thanks!