[commit] Add news entry for gdb.printing.register_pretty_printer

[Doug Evans]

Hi.
I think this should have a NEWS entry so I added one.

2011-10-16  Doug Evans  <dje@google.com>

	* NEWS: Document python gdb.printing.register_pretty_printer's new
	`replace' parameter.

Index: NEWS
===================================================================
RCS file: /cvs/src/src/gdb/NEWS,v
retrieving revision 1.457
diff -u -p -r1.457 NEWS
--- NEWS	9 Oct 2011 22:21:42 -0000	1.457
+++ NEWS	16 Oct 2011 19:39:40 -0000
@@ -15,6 +15,10 @@
 
 * Python scripting
 
+  ** The register_pretty_printer function in module gdb.printing now takes
+     an optional `replace' argument.  If True the new printer replaces any
+     existing one.
+
   ** The "maint set python print-stack on|off" command has been
      deprecated, and a new command: "set python print-stack on|off" has
      replaced it.  Additionally, the default for "print-stack" is now