maint: use new emit_try_help in place of equivalent fprintf

Run this command:
  perl -0777 -pi -e \
   's/fprintf \(stderr, _\("Try `%s --help.*\n.*;/emit_try_help ();/m'\
     src/*.c

1 files changed, 1 insertions, 2 deletions

diff --git a/src/df.c b/src/df.c
index fae32cd93..e3d55c443 100644
--- a/src/df.c
+++ b/src/df.c
@@ -840,8 +840,7 @@ void
 usage (int status)
 {
   if (status != EXIT_SUCCESS)
-    fprintf (stderr, _("Try `%s --help' for more information.\n"),
-             program_name);
+    emit_try_help ();
   else
     {
       printf (_("Usage: %s [OPTION]... [FILE]...\n"), program_name);