Improve documentation of 'line-number-display-width'

* doc/lispref/display.texi (Size of Displayed Text): Document the
additional 2 columns used for line-number display.

* src/indent.c (Fline_number_display_width): Doc fix.  (Bug#28248)

1 files changed, 2 insertions, 1 deletions

diff --git a/src/indent.c b/src/indent.c
index be8676600a5..a3e9b5b0b9a 100644
--- a/src/indent.c
+++ b/src/indent.c
@@ -1993,7 +1993,8 @@ DEFUN ("line-number-display-width", Fline_number_display_width,
        doc: /* Return the width used for displaying line numbers in the selected window.
 If optional argument PIXELWISE is non-nil, return the width in pixels,
 otherwise return the width in columns of the face used to display
-line numbers, `line-number'.  */)
+line numbers, `line-number'.  Note that in the latter case, the value
+doesn't include the 2 columns used for padding the numbers.  */)
   (Lisp_Object pixelwise)
 {
   int width, pixel_width;