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, 125 insertions, 119 deletions

diff --git a/test/command/6137.md b/test/command/6137.md
index d6cd34b92..a58b4876f 100644
--- a/test/command/6137.md
+++ b/test/command/6137.md
@@ -16,136 +16,142 @@ This reference to Figure \ref{fig:label} works fine.
 \end{figure}
 ^D
 [ Para
-  [ Str "This"
-  , Space
-  , Str "reference"
-  , Space
-  , Str "to"
-  , Space
-  , Str "Table"
-  , Space
-  , Link
-    ( ""
-    , []
-    ,
-      [ ( "reference-type", "ref" ), ( "reference", "tbl:label" ) ]
-    )
-    [ Str "1" ]
-    ( "#tbl:label", "" )
-  , Space
-  , Str "doesn\8217t"
-  , Space
-  , Str "work."
-  ]
-, Div
-  ( "tbl:label", [], [] )
-  [ Table
-    ( "", [], [] )
-    ( Caption Nothing
-      [ Plain
-        [ Str "This"
-        , Space
-        , Str "caption"
-        , Space
-        , Str "has"
-        , Space
-        , Str "no"
-        , Space
-        , Str "number."
-        ]
-      ]
-    )
-    [
-      ( AlignLeft, ColWidthDefault )
-    ,
-      ( AlignCenter, ColWidthDefault )
-    ,
-      ( AlignRight, ColWidthDefault )
+    [ Str "This"
+    , Space
+    , Str "reference"
+    , Space
+    , Str "to"
+    , Space
+    , Str "Table"
+    , Space
+    , Link
+        ( ""
+        , []
+        , [ ( "reference-type" , "ref" )
+          , ( "reference" , "tbl:label" )
+          ]
+        )
+        [ Str "1" ]
+        ( "#tbl:label" , "" )
+    , Space
+    , Str "doesn\8217t"
+    , Space
+    , Str "work."
     ]
-    ( TableHead ( "", [], [] ) [] )
-    [ TableBody
-      ( "", [], [] )
-      ( RowHeadColumns 0 ) []
-      [ Row
-        ( "", [], [] )
-        [ Cell
-          ( "", [], [] ) AlignDefault
-          ( RowSpan 1 )
-          ( ColSpan 1 )
-          [ Plain [ Str "\8212\8212\8211" ] ]
-        , Cell
-          ( "", [], [] ) AlignDefault
-          ( RowSpan 1 )
-          ( ColSpan 1 )
-          [ Plain [ Str "\8212\8212\8211" ] ]
-        , Cell
-          ( "", [], [] ) AlignDefault
-          ( RowSpan 1 )
-          ( ColSpan 1 )
-          [ Plain [ Str "\8212\8212\8211" ] ]
+, Div
+    ( "tbl:label" , [] , [] )
+    [ Table
+        ( "" , [] , [] )
+        (Caption
+           Nothing
+           [ Plain
+               [ Str "This"
+               , Space
+               , Str "caption"
+               , Space
+               , Str "has"
+               , Space
+               , Str "no"
+               , Space
+               , Str "number."
+               ]
+           ])
+        [ ( AlignLeft , ColWidthDefault )
+        , ( AlignCenter , ColWidthDefault )
+        , ( AlignRight , ColWidthDefault )
         ]
-      , Row
-        ( "", [], [] )
-        [ Cell
-          ( "", [], [] ) AlignDefault
-          ( RowSpan 1 )
-          ( ColSpan 1 )
-          [ Plain [ Str "\8212\8212\8211" ] ]
-        , Cell
-          ( "", [], [] ) AlignDefault
-          ( RowSpan 1 )
-          ( ColSpan 1 )
-          [ Plain [ Str "\8212\8212\8211" ] ]
-        , Cell
-          ( "", [], [] ) AlignDefault
-          ( RowSpan 1 )
-          ( ColSpan 1 )
-          [ Plain [ Str "\8212\8212\8211" ] ]
+        (TableHead ( "" , [] , [] ) [])
+        [ TableBody
+            ( "" , [] , [] )
+            (RowHeadColumns 0)
+            []
+            [ Row
+                ( "" , [] , [] )
+                [ Cell
+                    ( "" , [] , [] )
+                    AlignDefault
+                    (RowSpan 1)
+                    (ColSpan 1)
+                    [ Plain [ Str "\8212\8212\8211" ] ]
+                , Cell
+                    ( "" , [] , [] )
+                    AlignDefault
+                    (RowSpan 1)
+                    (ColSpan 1)
+                    [ Plain [ Str "\8212\8212\8211" ] ]
+                , Cell
+                    ( "" , [] , [] )
+                    AlignDefault
+                    (RowSpan 1)
+                    (ColSpan 1)
+                    [ Plain [ Str "\8212\8212\8211" ] ]
+                ]
+            , Row
+                ( "" , [] , [] )
+                [ Cell
+                    ( "" , [] , [] )
+                    AlignDefault
+                    (RowSpan 1)
+                    (ColSpan 1)
+                    [ Plain [ Str "\8212\8212\8211" ] ]
+                , Cell
+                    ( "" , [] , [] )
+                    AlignDefault
+                    (RowSpan 1)
+                    (ColSpan 1)
+                    [ Plain [ Str "\8212\8212\8211" ] ]
+                , Cell
+                    ( "" , [] , [] )
+                    AlignDefault
+                    (RowSpan 1)
+                    (ColSpan 1)
+                    [ Plain [ Str "\8212\8212\8211" ] ]
+                ]
+            ]
         ]
-      ]
+        (TableFoot ( "" , [] , [] ) [])
     ]
-    ( TableFoot ( "", [], [] ) [] )
-  ]
-, Para
-  [ Str "This"
-  , Space
-  , Str "reference"
-  , Space
-  , Str "to"
-  , Space
-  , Str "Figure"
-  , Space
-  , Link
-    ( ""
-    , []
-    ,
-      [ ( "reference-type", "ref" ), ( "reference", "fig:label" ) ]
-    )
-    [ Str "1" ]
-    ( "#fig:label", "" )
-  , Space
-  , Str "works"
-  , Space
-  , Str "fine."
-  ]
 , Para
-  [ Image
-    ( "fig:label", [], [ ( "width", "\\textwidth" ) ] )
-    [ Str "A"
+    [ Str "This"
     , Space
-    , Str "numbered"
+    , Str "reference"
     , Space
-    , Str "caption,"
+    , Str "to"
     , Space
-    , Str "if"
+    , Str "Figure"
     , Space
-    , Str "I"
+    , Link
+        ( ""
+        , []
+        , [ ( "reference-type" , "ref" )
+          , ( "reference" , "fig:label" )
+          ]
+        )
+        [ Str "1" ]
+        ( "#fig:label" , "" )
     , Space
-    , Str "use"
+    , Str "works"
     , Space
-    , Str "pandoc-crossref."
+    , Str "fine."
+    ]
+, Para
+    [ Image
+        ( "fig:label" , [] , [ ( "width" , "\\textwidth" ) ] )
+        [ Str "A"
+        , Space
+        , Str "numbered"
+        , Space
+        , Str "caption,"
+        , Space
+        , Str "if"
+        , Space
+        , Str "I"
+        , Space
+        , Str "use"
+        , Space
+        , Str "pandoc-crossref."
+        ]
+        ( "example.png" , "fig:" )
     ]
-    ( "example.png", "fig:" )
-  ]
 ]
 ```