bug#12078: 24.1; Improve the I-search prompt

[Juri Linkov <juri@jurta.org>]

>   Failing I-search: foobar
>   Overwrapped I-search: foobar
>   Failing overwrapped I-search: foobar
>   Failing I-search: foobar [initial node]
>
> would be
>
>   I-search: foobar  [failing]
>   I-search: foobar  [overwrapped]
>   I-search: foobar  [failing, overwrapped]
>   I-search: foobar  [failing, initial node]

I think we should distinguish between momentary messages and search states.
For instance, "failing" is a momentary message, but "overwrapped"
is a search state.  It would be very annoying to display persistent
search states like "overwrapped" at the end of the search prompt.

Meanwhile, for consistency with the isearch message "end of manual",
I propose to rename its counterpart "initial node" to "end of node":

=== modified file 'lisp/info.el'
--- lisp/info.el	2012-07-10 11:51:54 +0000
+++ lisp/info.el	2012-07-29 00:23:39 +0000
@@ -342,12 +340,12 @@ (defcustom Info-search-whitespace-regexp
 (defcustom Info-isearch-search t
   "If non-nil, isearch in Info searches through multiple nodes.
 Before leaving the initial Info node, where isearch was started,
-it fails once with the error message [initial node], and with
+it fails once with the error message [end of node], and with
 subsequent C-s/C-r continues through other nodes without failing
 with this error message in other nodes.  When isearch fails for
-the rest of the manual, it wraps around the whole manual and
-restarts the search from the top/final node depending on
-search direction.
+the rest of the manual, it displays the error message [end of manual],
+wraps around the whole manual and restarts the search from the top/final
+node depending on search direction.
 
 Setting this option to nil restores the default isearch behavior
 with wrapping around the current Info node."
@@ -1863,7 +1867,7 @@ (defun Info-search (regexp &optional bou
 		 (not bound)
 		 (or give-up (and found (not (and (> found opoint-min)
 						  (< found opoint-max))))))
-	(signal 'search-failed (list regexp "initial node")))
+	(signal 'search-failed (list regexp "end of node")))
 
       ;; If no subfiles, give error now.
       (if give-up