Add H binding to info, for compatibility with standalone info

Ref: http://lists.gnu.org/archive/html/emacs-devel/2014-02/msg00309.html

* lisp/info.el (Info-mode-map): Add H for describe-mode,
to synchronize with standalone Info.

* doc/misc/info.texi (Top): Mention H for a summary of all commands.

doc/misc/ChangeLog

+2014-02-28  Karl Berry  <karl@gnu.org>
+
+	* info.texi (Top): Mention H for a summary of all commands.
+
 2014-02-25  Glenn Morris  <rgm@gnu.org>
 
 	* edt.texi (Quick start, Starting emulation): Update hook details.

doc/misc/info.texi

@@ -69,6 +69,8 @@ instruction sequence.
 To read about advanced Info commands, type @kbd{n} twice.  This
 brings you to @cite{Advanced Info Commands}, skipping over the `Getting
 Started' chapter.
+
+Type @kbd{H} to see a summary of all available commands.
 @end ifinfo
 @end ifnottex
 

lisp/ChangeLog

+2014-02-28  Karl Berry  <karl@gnu.org>
+
+	* info.el (Info-mode-map): Add H for describe-mode,
+	to synchronize with standalone Info.
+
 2014-02-28  Emilio C. Lopes  <eclig@gmx.net>
 
 	* progmodes/sql.el (sql-interactive-mode):

lisp/info.el

@@ -3962,6 +3962,7 @@ If FORK is non-nil, it is passed to `Info-goto-node'."
     (define-key map "f" 'Info-follow-reference)
     (define-key map "g" 'Info-goto-node)
     (define-key map "h" 'Info-help)
+    (define-key map "H" 'describe-mode)
     (define-key map "i" 'Info-index)
     (define-key map "I" 'Info-virtual-index)
     (define-key map "l" 'Info-history-back)