RFA: update NEWS for new 7.2 features

[Tom Tromey]

This patch adds NEWS entries for the label patch and for .gdb_index.

Please review.

Tom

2010-07-27  Tom Tromey  <tromey@redhat.com>

	* NEWS: Mention labels, .gdb_index.

Index: NEWS
===================================================================
RCS file: /cvs/src/src/gdb/NEWS,v
retrieving revision 1.394
diff -u -r1.394 NEWS
--- NEWS	22 Jul 2010 10:52:02 -0000	1.394
+++ NEWS	27 Jul 2010 18:40:31 -0000
@@ -3,6 +3,15 @@
 
 *** Changes since GDB 7.2
 
+* GDB now has some support for using labels in the program's source in
+  linespecs.  For instance, you can use "advance label" to continue
+  execution to a label.
+
+* GDB now has support for reading and writing a new .gdb_index
+  section.  This section holds a fast index of DWARF debugging
+  information and can be used to greatly speed up GDB startup and
+  operation.  See the documentation for `save gdb-index' for details.
+
 *** Changes in GDB 7.2
 
 * Shared library support for remote targets by default