Include the major mode name in the `C-h b' output

* lisp/calc/calc-help.el (calc-describe-bindings): Don't add the
name since it's there now.

* src/keymap.c (Fdescribe_buffer_bindings): Include the major mode
name for symmetry with the minor modes (and because it's easy to
forget).

lisp/calc/calc-help.el

@@ -111,9 +111,6 @@ C-w  Describe how there is no warranty for Calc."
   (with-current-buffer "*Help*"
     (let ((inhibit-read-only t))
       (goto-char (point-min))
-      (when (search-forward "Major Mode Bindings:" nil t)
-        (delete-region (point-min) (point))
-        (insert "Calc Mode Bindings:"))
       (when (search-forward "Global bindings:" nil t)
         (forward-line -1)
         (delete-region (point) (point-max)))

src/keymap.c

@@ -2933,7 +2933,10 @@ You type        Translation\n\
 	{
 	  if (EQ (start1, BVAR (XBUFFER (buffer), keymap)))
 	    {
-	      Lisp_Object msg = build_unibyte_string ("\f\nMajor Mode Bindings");
+	      Lisp_Object msg =
+		CALLN (Fformat,
+		       build_unibyte_string ("\f\n`%s' Major Mode Bindings"),
+		       XBUFFER (buffer)->major_mode_);
 	      CALLN (Ffuncall,
 		     Qdescribe_map_tree,
 		     start1, Qt, shadow, prefix,