fix: dune promotion list should write its output to stdout (#13462)

Rather than stderr

---------

Signed-off-by: Rudi Grinberg <[email protected]>

Author: rgrinberg

bin/promotion.ml

@@ -116,7 +116,7 @@ module Files = struct
     List.sort present ~compare:(fun x y ->
       Path.Source.compare (Diff_promotion.File.source x) (Diff_promotion.File.source y))
     |> List.iter ~f:(fun file ->
-      Diff_promotion.File.source file |> Path.Source.to_string |> Console.printf "%s")
+      Diff_promotion.File.source file |> Path.Source.to_string |> print_endline)
   ;;
 
   let command = Cmd.v info term

doc/changes/fixed/13462.md

@@ -0,0 +1 @@
+- `$ dune promotion list` writes output to stdout rather than stderr (#13462)

test/blackbox-tests/test-cases/promote/promotion-list.t

@@ -40,13 +40,13 @@
   +B actual
   [1]
 
-  $ dune promotion list --diff-command 'diff -u' 2>&1
+  $ dune promotion list --diff-command 'diff -u'
   a.expected
   b.expected
 
-  $ dune promotion list b.expected --diff-command 'diff -u' 2>&1
+  $ dune promotion list b.expected --diff-command 'diff -u'
   b.expected
 
-  $ dune promotion list a.expected nothing-to-promote.txt --diff-command 'diff -u' 2>&1
+  $ dune promotion list a.expected nothing-to-promote.txt --diff-command 'diff -u'
   Warning: Nothing to promote for nothing-to-promote.txt.
   a.expected