Allow psql to print COPY command status in more cases.

Previously, psql would print the "COPY nnn" command status only for COPY
commands executed server-side.  Now it will print that for frontend copies
too (including \copy).  However, we continue to suppress the command status
for COPY TO STDOUT, since in that case the copy data has been routed to the
same place that the command status would go, and there is a risk of the
status line being mistaken for another line of COPY data.  Doing that would
break existing scripts, and it doesn't seem worth the benefit --- this case
seems fairly analogous to SELECT, for which we also suppress the command
status.

Kumar Rajeev Rastogi, with substantial review by Amit Khandekar

doc/src/sgml/ref/copy.sgml

@@ -370,6 +370,16 @@ COPY <replaceable class="parameter">count</replaceable>
    The <replaceable class="parameter">count</replaceable> is the number
    of rows copied.
   </para>
+
+  <note>
+   <para>
+    <application>psql</> will print this command tag only if the command
+    was not <literal>COPY ... TO STDOUT</>, or the
+    equivalent <application>psql</> meta-command
+    <literal>\copy ... to stdout</>.  This is to prevent confusing the
+    command tag with the data that was just printed.
+   </para>
+  </note>
  </refsect1>
 
  <refsect1>