[libsigcplusplus] connection: Update the documentation.

[Murray Cumming <murrayc src gnome org>]

commit eb53dd6bc9aa1ed6d44cb2b8ebba3093e7e5e4bb
Author: Murray Cumming <murrayc murrayc com>
Date:   Fri Apr 29 09:22:28 2016 +0200

    connection: Update the documentation.
    
    This no longer needs to (or can be) created from an iterator.

 sigc++/connection.h |   11 ++---------
 1 files changed, 2 insertions(+), 9 deletions(-)
---
diff --git a/sigc++/connection.h b/sigc++/connection.h
index f70ac4b..04aa74a 100644
--- a/sigc++/connection.h
+++ b/sigc++/connection.h
@@ -24,18 +24,11 @@
 namespace sigc
 {
 
-/** Convenience class for safe disconnection.
- * Iterators must not be used beyond the lifetime of the list
- * they work on. A connection object can be created from a
- * slot list iterator and may safely be used to disconnect
- * the referred slot at any time (disconnect()). If the slot
- * has already been destroyed, disconnect() does nothing. empty() or
+/** This may be used to disconnect the referred slot at any time (disconnect()).
+ * If the slot has already been destroyed, disconnect() does nothing. empty() or
  * operator bool() can be used to test whether the connection is
  * still active. The connection can be blocked (block(), unblock()).
  *
- * This is possible because the connection object gets notified
- * when the referred slot dies (notify()).
- *
  * @ingroup signal
  */
 struct SIGC_API connection : public notifiable