bug#4193: 23.1; doc string of bookmark-alist - mention handler entries

[Drew Adams]

Doc string:
 
       (BOOKMARK1 BOOKMARK2 ...)
 
where each BOOKMARK is of the form
 
  (NAME PARAM-ALIST) or (NAME . PARAM-ALIST)
 
where the first form is the old deprecated one and the second is
the new favored one.  PARAM-ALIST is typically of the form:
 
 ((filename . FILE)
  (front-context-string . FRONT-STR)
  (rear-context-string  . REAR-STR)
  (position . POS)
  (annotation . ANNOTATION)))
 
Handler entries should be included here. They are used for Info
etc. They are now a regular part of the bookmark structure - at least
as important as annotations.
 

In GNU Emacs 23.1.1 (i386-mingw-nt5.1.2600)
 of 2009-07-29 on SOFT-MJASON
Windowing system distributor `Microsoft Corp.', version 5.1.2600
configured using `configure --with-gcc (4.4)'