Display the exit code if the last command failed in Eshell

* lisp/eshell/esh-io.el (eshell-last-command-status): Make
buffer-local.

* lisp/eshell/em-prompt.el (eshell-prompt-function): Insert the exit
code if last command failed.

* test/lisp/eshell/em-prompt-tests.el (em-prompt-test/after-failure):
New test.
(em-prompt-test/next-previous-prompt-1)
(em-prompt-test/forward-backward-matching-input-1): Add a failing
command to tests.

* doc/misc/eshell.texi (Invocation): Document change.

* etc/NEWS: Announce change (bug#65604).

1 files changed, 3 insertions, 0 deletions

diff --git a/etc/NEWS b/etc/NEWS
index 5c11b6b9ac7..81ef0d6cedb 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -370,6 +370,9 @@ to load the edited aliases.
 Running 'rgrep' in Eshell now uses the Emacs grep facility instead of
 calling external rgrep.
 
++++
+*** If a command exits abnormally, the Eshell prompt now shows its exit code.
+
 ** Pcomplete
 
 ---