org-table.el: Enhance `org-table-set-header-line-format'

* lisp/org-table.el (org-table-set-header-line-format): Use
'line-number face if relevant.

lisp/org-table.el

@@ -497,12 +497,12 @@ existing value of `header-line-format' we might want to restore."
 			(point))))
 	   (if (< tbeg (save-excursion (move-to-window-line 0) (point)))
 	       (setq header-line-format
-		     (propertize
-		      (concat (propertize " " 'display '(space :width left-fringe))
-			      (when lin (make-string (+ lin 2) 32))
-			      (when pre (make-string pre 32))
-			      (org-table-row-get-visible-string tbeg))
-		      'face 'org-table))
+		     (concat (propertize " " 'display '(space :width left-fringe))
+			     (when lin (propertize (make-string (+ lin 2) 32)
+						   'face 'line-number))
+			     (when pre (make-string pre 32))
+			     (propertize (org-table-row-get-visible-string tbeg)
+					 'face 'org-table)))
 	     (setq header-line-format org-table-temp-header-line)))))
     (setq header-line-format org-table-temp-header-line)))