eval-defun documentation should mention defcustom

[Algebraist Petrofsky]

In GNU Emacs 21.1.1 (i586-pc-linux-gnu, X toolkit, Xaw3d scroll bars)
 of 2001-10-24 on radish.petrofsky.org


Bug triggered by: C-h k M-C-x

The documentation for eval-defun doesn't mention its special handling
of defcustom.  It reads, in part:

   If the current defun is actually a call to `defvar', then reset the
   variable using its initial value expression even if the variable
   already has some other value.  (Normally `defvar' does not change the
   variable's value if it already has a value.)

I suggest adding a sentence like so:

   If the current defun is actually a call to `defvar', then reset the
   variable using its initial value expression even if the variable
   already has some other value.  (Normally `defvar' does not change the
   variable's value if it already has a value.)   Likewise for `defcustom'.