Trivial fix: clarify a comment.

src/include/nodes/plannodes.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2004, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/nodes/plannodes.h,v 1.75 2004/08/29 05:06:57 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/plannodes.h,v 1.76 2004/10/27 07:26:56 neilc Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -85,7 +85,7 @@ typedef struct Plan
 	 */
 	int			nParamExec;		/* Number of them in entire query. This is
 								 * to get Executor know about how many
-								 * param_exec there are in query plan. */
+								 * PARAM_EXEC there are in query plan. */
 } Plan;
 
 /* ----------------