Server variable documentation

[Simon Josefsson <jas@extundo.com>]

It was pointed out that nnimap.el didn't have the doc string for
variables that some other backends (nnbabyl.el, nnfolder.el,
nnmbox.el, nnmh.el, and nnml.el) has:

,----
| (defvoo nnml-directory message-directory
|   "Spool directory for the nnml mail backend.
| 
| This variable is a virtual server slot.  See the Gnus manual for details.")
`----

Perhaps we can do something less manual than modifying the remaining
nn*.el files with the following patch.  Not only do you get a fancy
hyperlink to the proper section in the manual, but the documentation
is added automatically, and it uses the term "server variable" which I
think is more in line with what the Gnus documentation uses.  Of
course, the previous doc string patch has to be reverted.

What'ya'think?  Maybe `deffoo' should have this as well.

--- nnoo.el.~6.4.~	Tue Nov  6 18:06:50 2001
+++ nnoo.el	Sun Dec  9 01:37:59 2001
@@ -38,7 +38,7 @@
   "The same as `defvar', only takes list of variables to MAP to."
   `(prog1
        ,(if doc
-	    `(defvar ,var ,init ,doc)
+	    `(defvar ,var ,init ,(concat doc "\n\nThis is a Gnus server variable.  See Info node `(gnus)Select Methods'."))
 	  `(defvar ,var ,init))
      (nnoo-define ',var ',map)))
 (put 'defvoo 'lisp-indent-function 2)