[RFC - doc] Add note about the possibility of symbols getting moved across blocks

Hello,

This patch is in response to the discussion here:
http://sourceware.org/ml/gdb-patches/2012-04/msg00845.html

2012-04-25  Siva Chandra Reddy  <sivachandra@...>

        * gdb.texinfo (Blocks In Python): Add a note saying that future
        improvements to symbol and symbol table representations can move
        symbols across blocks within a symbol table.

Thanks,
Siva Chandra

Index: gdb.texinfo
===================================================================
RCS file: /cvs/src/src/gdb/doc/gdb.texinfo,v
retrieving revision 1.948
diff -u -p -r1.948 gdb.texinfo
--- gdb.texinfo 23 Apr 2012 17:26:01 -0000 1.948
+++ gdb.texinfo 25 Apr 2012 07:53:58 -0000
@@ -24530,7 +24530,10 @@ detailed technical information on @value
 stack.
 
 A @code{gdb.Block} is iterable.  The iterator returns the symbols
-(@pxref{Symbols In Python}) local to the block.
+(@pxref{Symbols In Python}) local to the block.  Users using this
+feature should keep in mind that future improvements to the internal
+representation, of symbols and symbol tables, can move symbols across
+blocks within a symbol table.
 
 The following block-related functions are available in the @code{gdb}
 module: