Remove trailing comma in 0-dim reshape summary (#56853)

Currently, there is an extra comma in displaying the summary for a 0-dim
`ReshapedArray`:
```julia
julia> reshape(1:1)
0-dimensional reshape(::UnitRange{Int64}, ) with eltype Int64:
1
```
This PR only prints the comma if `dims` isn't empty, so that we now
obtain
```julia
julia> reshape(1:1)
0-dimensional reshape(::UnitRange{Int64}) with eltype Int64:
1
```

Author: jishnub

base/show.jl

@@ -3265,7 +3265,9 @@ showindices(io) = nothing
 function showarg(io::IO, r::ReshapedArray, toplevel)
     print(io, "reshape(")
     showarg(io, parent(r), false)
-    print(io, ", ", join(r.dims, ", "))
+    if !isempty(r.dims)
+        print(io, ", ", join(r.dims, ", "))
+    end
     print(io, ')')
     toplevel && print(io, " with eltype ", eltype(r))
     return nothing

test/show.jl

@@ -1861,6 +1861,9 @@ end
     B = @view ones(2)[r]
     Base.showarg(io, B, false)
     @test String(take!(io)) == "view(::Vector{Float64}, $(repr(r)))"
+
+    Base.showarg(io, reshape(UnitRange{Int64}(1,1)), false)
+    @test String(take!(io)) == "reshape(::UnitRange{Int64})"
 end
 
 @testset "Methods" begin