move ImageShow to make.jl and add missing docs dependency

When building documentation locally we need to manually do `]dev .` to tell
Julia use dev version of MLDatasets, and this immediately updates the
Project.toml file, to keep it complete I commit this change . This change won't
affect docs CI.

Author: johnnychen94

docs/Project.toml

@@ -3,3 +3,4 @@ Documenter = "e30172f5-a6a5-5a46-863b-614d45cd2de4"
 ImageCore = "a09fc81d-aa75-5fe9-8630-4744c3626534"
 ImageIO = "82e4d734-157c-48bb-816b-45c225c6df19"
 ImageShow = "4e3cecfd-b093-5904-9786-8bbb286a6a31"
+MLDatasets = "eb30cadb-4394-5ae3-aed4-317e484a6458"

docs/make.jl

@@ -1,4 +1,5 @@
 using Documenter, MLDatasets
+using ImageShow # for better image display
 
 ## Commented out since gives warning
 # DocMeta.setdocmeta!(MLDatasets, :DocTestSetup, :(using MLDatasets); recursive=true)
@@ -34,7 +35,7 @@ makedocs(
                 "Iris" => "datasets/Iris.md",
                 "Boston Housing" => "datasets/BostonHousing.md",
             ],
-            
+
             "Text" => Any[
                 "PTBLM" => "datasets/PTBLM.md",
                 "UD_English" => "datasets/UD_English.md",
@@ -54,4 +55,4 @@ makedocs(
 )
 
 
-deploydocs(repo = "github.com/JuliaML/MLDatasets.jl.git")
+deploydocs(repo = "github.com/JuliaML/MLDatasets.jl.git")

docs/src/index.md

@@ -63,12 +63,10 @@ of images.
 
 ```@example
 using MLDatasets
-# Alternatively, you can also just call `using Images`
-using ImageCore, ImageShow
+using ImageCore
 
-# The original dataset is stored in row-major order,
-# to display it normally in Julia, we need to permute the
-# first two dimensions.
+# The original dataset is stored in row-major order, to display it
+# normally in Julia, we need to permute the first two dimensions.
 test_x = Gray.(PermutedDimsArray(MNIST.testtensor(), (2, 1, 3)));
 test_x_sample = @view test_x[:, :, 1:64];