Use pretty-simple to format native output.

Previously we used our own homespun formatting.  But this
produces over-long lines that aren't ideal for diffs in tests.
Easier to use something off-the-shelf and standard.

Closes #7580.

Performance is slower by about a factor of 10, but this isn't
really a problem because native isn't suitable as a serialization
format. (For serialization you should use json, because the reader
is so much faster than native.)

1 files changed, 35 insertions, 11 deletions

diff --git a/test/command/168.md b/test/command/168.md
index 43c3b865a..02b426089 100644
--- a/test/command/168.md
+++ b/test/command/168.md
@@ -11,13 +11,25 @@ nested div
 :::
 :::::::::::::::::::::::::::::::
 ^D
-[Div ("",["warning"],[])
- [Para [Str "This",Space,Str "is",Space,Str "the",Space,Str "warning!"]
- ,OrderedList (1,Decimal,Period)
-  [[Plain [Str "list"]]
-  ,[Plain [Str "another"]]]
- ,Div ("myid",["class"],[("key","val")])
-  [Para [Str "nested",Space,Str "div"]]]]
+[ Div
+  ( "", [ "warning" ], [] )
+  [ Para
+    [ Str "This"
+    , Space
+    , Str "is"
+    , Space
+    , Str "the"
+    , Space
+    , Str "warning!"
+    ]
+  , OrderedList
+    ( 1, Decimal, Period )
+    [ [ Plain [ Str "list" ] ], [ Plain [ Str "another" ] ] ]
+  , Div
+    ( "myid", [ "class" ], [ ( "key", "val" ) ] )
+    [ Para [ Str "nested", Space, Str "div" ] ]
+  ]
+]
 ```
 
 ```
@@ -26,7 +38,7 @@ foo
 :::
 bar
 ^D
-[Para [Str "foo",SoftBreak,Str ":::",SoftBreak,Str "bar"]]
+[ Para [ Str "foo", SoftBreak, Str ":::", SoftBreak, Str "bar" ] ]
 ```
 
 ```
@@ -37,7 +49,19 @@ Here is a paragraph.
 And another.
 :::::
 ^D
-[Div ("",["Warning"],[])
- [Para [Str "Here",Space,Str "is",Space,Str "a",Space,Str "paragraph."]
- ,Para [Str "And",Space,Str "another."]]]
+[ Div
+  ( "", [ "Warning" ], [] )
+  [ Para
+    [ Str "Here"
+    , Space
+    , Str "is"
+    , Space
+    , Str "a"
+    , Space
+    , Str "paragraph."
+    ]
+  , Para
+    [ Str "And", Space, Str "another." ]
+  ]
+]
 ```