Update comments to reflect code rearrangement.

Commit f9143d10 falsified these.

KaiGai Kohei

src/include/nodes/execnodes.h

@@ -1611,7 +1611,8 @@ struct CustomExecMethods;
 typedef struct CustomScanState
 {
 	ScanState	ss;
-	uint32		flags;			/* mask of CUSTOMPATH_* flags, see relation.h */
+	uint32		flags;			/* mask of CUSTOMPATH_* flags, see
+								 * nodes/extensible.h */
 	List	   *custom_ps;		/* list of child PlanState nodes, if any */
 	Size		pscan_len;		/* size of parallel coordination information */
 	const struct CustomExecMethods *methods;

src/include/nodes/plannodes.h

@@ -560,7 +560,8 @@ struct CustomScanMethods;
 typedef struct CustomScan
 {
 	Scan		scan;
-	uint32		flags;			/* mask of CUSTOMPATH_* flags, see relation.h */
+	uint32		flags;			/* mask of CUSTOMPATH_* flags, see
+								 * nodes/extensible.h */
 	List	   *custom_plans;	/* list of Plan nodes, if any */
 	List	   *custom_exprs;	/* expressions that custom code may evaluate */
 	List	   *custom_private; /* private data for custom code */

src/include/nodes/relation.h

@@ -1087,7 +1087,8 @@ struct CustomPathMethods;
 typedef struct CustomPath
 {
 	Path		path;
-	uint32		flags;			/* mask of CUSTOMPATH_* flags, see above */
+	uint32		flags;			/* mask of CUSTOMPATH_* flags, see
+								 * nodes/extensible.h */
 	List	   *custom_paths;	/* list of child Path nodes, if any */
 	List	   *custom_private;
 	const struct CustomPathMethods *methods;