[topfmt] Set formatter + flush fix

Closes #12351.

We set the parameters of the redirect formatter to be same than the
ones in stdout.

I guess the original semantics was to ignore the parameters, so I'm
unsure we want to do this.

While we are a it, we include a fix on the formatter, which _must_ be
flushed before closing its associated channel.

3 files changed, 8 insertions, 0 deletions

diff --git a/test-suite/misc/redirect_printing.out b/test-suite/misc/redirect_printing.out
new file mode 100644
index 0000000000..4f45c4d4c2
--- /dev/null
+++ b/test-suite/misc/redirect_printing.out
@@ -0,0 +1,2 @@
+nat_ind
+     : forall P : nat -> Prop, P 0 -> (forall n : nat, P n -> P (S n)) -> forall n : nat, P n
diff --git a/test-suite/misc/redirect_printing.sh b/test-suite/misc/redirect_printing.sh
new file mode 100755
index 0000000000..7da17407f3
--- /dev/null
+++ b/test-suite/misc/redirect_printing.sh
@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+
+$coqc misc/redirect_printing.v
+diff -u redirect_test.out misc/redirect_printing.out
diff --git a/test-suite/misc/redirect_printing.v b/test-suite/misc/redirect_printing.v
new file mode 100644
index 0000000000..2f9096bcb8
--- /dev/null
+++ b/test-suite/misc/redirect_printing.v
@@ -0,0 +1,2 @@
+Set Printing Width 999999.
+Redirect "redirect_test" Check nat_ind.