Improve documentation of 'backtrace-on-error-noninteractive'

* src/eval.c (syms_of_eval) <backtrace-on-error-noninteractive>:
Format the doc string according to conventions.

* etc/NEWS: Improve formatting and wording of the entry describing
'backtrace-on-error-noninteractive.

2 files changed, 8 insertions, 6 deletions

diff --git a/etc/NEWS b/etc/NEWS
index d796a4cdbcd..f2fd9fb1386 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -192,10 +192,10 @@ have been replaced with "chat.freenode.net" throughout Emacs.
 These functions return the connection local value of the respective
 variables.  This can be used for remote hosts.
 
-** Emacs now prints a backtrace when signaling an error in batch mode.  This
-makes debugging Emacs Lisp scripts run in batch mode easier.  If you
-want to disable this behavior, set 'backtrace-on-error-noninteractive'
-to nil.
+** Emacs now prints a backtrace when signaling an error in batch mode.
+This makes debugging Emacs Lisp scripts run in batch mode easier.  To
+get back the old behavior, set the new variable
+'backtrace-on-error-noninteractive' to a nil value.
 
 
 * Editing Changes in Emacs 28.1
diff --git a/src/eval.c b/src/eval.c
index 1351d283c58..e2d70aaa0ef 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -4267,8 +4267,10 @@ still determine whether to handle the particular condition.  */);
 
   DEFVAR_BOOL ("backtrace-on-error-noninteractive",
                backtrace_on_error_noninteractive,
-               doc: /* If non-nil and Emacs is running noninteractively,
-print a backtrace on encountering an unhandled error.  */);
+               doc: /* Non-nil means print backtrace on error in batch mode.
+If this is nil, errors in batch mode will just print the error
+message upon encountering an unhandled error, without showing
+the Lisp backtrace.  */);
   backtrace_on_error_noninteractive = true;
 
   /* The value of num_nonmacro_input_events as of the last time we