Be a bit more verbose about the effects of string literal processing

changes in plpgsql.  Per bug #4843.

doc/src/sgml/release-8.4.sgml

-<!-- $PostgreSQL: pgsql/doc/src/sgml/release-8.4.sgml,v 1.8 2009/06/07 20:09:34 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/release-8.4.sgml,v 1.9 2009/06/08 14:57:21 tgl Exp $ -->
 <!-- See header comment in release.sgml about typical markup -->
 
  <sect1 id="release-8-4">
@@ -2303,6 +2303,14 @@
         Make processing of string literals and nested block comments
         match the main SQL parser's processing (Tom)
        </para>
+
+       <para>
+        In particular, the format string in <command>RAISE</> now works
+        the same as any other string literal, including being subject
+        to <varname>standard_conforming_strings</>.  This change also
+        fixes other cases in which valid commands would fail when
+        <varname>standard_conforming_strings</> is on.
+       </para>
       </listitem>
 
       <listitem>