Doc: remove obsolete description of oid column as being "hidden".

tglsfdc · tglsfdc · commit 145b18688c04 · 2019-07-01T12:09:06.000-04:00
Looks like one copy of this text didn't get updated. Justin Pryzby Discussion: https://postgr.es/m/20190701155932.GA22866@telsasoft.com
diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
@@ -615,7 +615,7 @@
       <entry><structfield>oid</structfield></entry>
       <entry><type>oid</type></entry>
       <entry></entry>
-      <entry>Row identifier (hidden attribute; must be explicitly selected)</entry>
+      <entry>Row identifier</entry>
      </row>
 
      <row>
