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, 8 insertions, 4 deletions

diff --git a/test/command/4054.md b/test/command/4054.md
index 3689773c4..9afef48b5 100644
--- a/test/command/4054.md
+++ b/test/command/4054.md
@@ -2,13 +2,17 @@
 % pandoc -t native -s -M title=New
 % Old
 ^D
-Pandoc (Meta {unMeta = fromList [("title",MetaString "New")]})
-[]
+Pandoc
+  ( Meta { unMeta = fromList [ ( "title", MetaString "New" ) ] } ) []
 ```
 
 ```
 % pandoc -t native -s -M foo=1 -M foo=2
 ^D
-Pandoc (Meta {unMeta = fromList [("foo",MetaList [MetaString "1",MetaString "2"])]})
-[]
+Pandoc
+  ( Meta
+    { unMeta = fromList
+      [ ( "foo", MetaList [ MetaString "1", MetaString "2" ] ) ]
+    }
+  ) []
 ```