Switch from pretty-simple to pretty-show for native output.

Update tests.

Reason:  it turns out that the native output generated by
pretty-simple isn't always readable by the native reader.
According to https://github.com/cdepillabout/pretty-simple/issues/99
it is not a design goal of the library that the rendered values
be readable using 'read'.  This makes it unsuitable for our
purposes.

pretty-show is a bit slower and it uses 4-space indents
(non-configurable), but it doesn't have this serious drawback.

1 files changed, 23 insertions, 18 deletions

diff --git a/test/command/4068.md b/test/command/4068.md
index 53fb660d0..83527a6fd 100644
--- a/test/command/4068.md
+++ b/test/command/4068.md
@@ -5,24 +5,29 @@
 [http://domain.com?a=. open productname bugs]
 ^D
 [ Para
-  [ Link
-    ( "", [], [] )
-    [ Str "open", Space, Str "productname", Space, Str "bugs" ]
-    ( "https://domain.com/script.php?a=1&b=2&c=&d=4", "" )
-  ]
+    [ Link
+        ( "" , [] , [] )
+        [ Str "open"
+        , Space
+        , Str "productname"
+        , Space
+        , Str "bugs"
+        ]
+        ( "https://domain.com/script.php?a=1&b=2&c=&d=4" , "" )
+    ]
 , Para
-  [ Str "["
-  , Link
-    ( "", [], [] )
-    [ Str "http://domain.com?a=" ]
-    ( "http://domain.com?a=", "" )
-  , Str "."
-  , Space
-  , Str "open"
-  , Space
-  , Str "productname"
-  , Space
-  , Str "bugs]"
-  ]
+    [ Str "["
+    , Link
+        ( "" , [] , [] )
+        [ Str "http://domain.com?a=" ]
+        ( "http://domain.com?a=" , "" )
+    , Str "."
+    , Space
+    , Str "open"
+    , Space
+    , Str "productname"
+    , Space
+    , Str "bugs]"
+    ]
 ]
 ```