bug#10783: Some built-in functionslost their argument names

[Eli Zaretskii <eliz@gnu.org>]

> From: Glenn Morris <rgm@gnu.org>
> Date: Fri, 10 Feb 2012 18:30:59 -0500
> Cc: 10783@debbugs.gnu.org
> 
> Deleting the doc-strings altogether from the duplicate definitions in
> pc-win.el would make this problem go away.

Maybe I'm missing something, but deleting the doc string from
pc-win.el shows x-get-selection-internal as "not documented" in the
MS-DOS build.

So for now, I sync'ed the doc strings with the X sources.

Note that some doc strings seem to require "more work™".  E.g., this:

  DEFUN ("x-disown-selection-internal", Fx_disown_selection_internal,
	 Sx_disown_selection_internal, 1, 3, 0,
	 doc: /* If we own the selection SELECTION, disown it.
  Disowning it means there is no such selection.

  TERMINAL should be a terminal object or a frame specifying the X
  server to query.  If omitted or nil, that stands for the selected
  frame's display, or the first available X display.  */)
    (Lisp_Object selection, Lisp_Object time_object, Lisp_Object terminal)

(TIME_OBJECT is not mentioned).  Or this:

  DEFUN ("x-get-selection-internal", Fx_get_selection_internal,
	 Sx_get_selection_internal, 2, 4, 0,
	 doc: /* Return text selected from some X window.
  SELECTION is a symbol, typically `PRIMARY', `SECONDARY', or `CLIPBOARD'.
  \(Those are literal upper-case symbol names, since that's what X expects.)
  TYPE is the type of data desired, typically `STRING'.
  TIME_STAMP is the time to use in the XConvertSelection call for foreign
  selections.  If omitted, defaults to the time for the last event.

  TERMINAL should be a terminal object or a frame specifying the X
  server to query.  If omitted or nil, that stands for the selected
  frame's display, or the first available X display.  */)
    (Lisp_Object selection_symbol, Lisp_Object target_type,
     Lisp_Object time_stamp, Lisp_Object terminal)

(refers to SELECTION, TYPE and TIME_STAMP, whereas the actual
parameters are SELECTION-SYMBOL, TARGET-TYPE, and TIME-STAMP).