Clarify documentation of char-table extra slots

* doc/lispref/sequences.texi (Char-Tables): Clarify that extra
slot numbers are zero-based.  (Bug#21467)

1 files changed, 3 insertions, 3 deletions

diff --git a/doc/lispref/sequences.texi b/doc/lispref/sequences.texi
index d0190457179..18120dad575 100644
--- a/doc/lispref/sequences.texi
+++ b/doc/lispref/sequences.texi
@@ -1276,13 +1276,13 @@ This function sets the parent of @var{char-table} to @var{new-parent}.
 @end defun
 
 @defun char-table-extra-slot char-table n
-This function returns the contents of extra slot @var{n} of
-@var{char-table}.  The number of extra slots in a char-table is
+This function returns the contents of extra slot @var{n} (zero based)
+of @var{char-table}.  The number of extra slots in a char-table is
 determined by its subtype.
 @end defun
 
 @defun set-char-table-extra-slot char-table n value
-This function stores @var{value} in extra slot @var{n} of
+This function stores @var{value} in extra slot @var{n} (zero based) of
 @var{char-table}.
 @end defun