Move a comment

Move a comment from the to-be-deleted section of nodes.h to where it
might still be useful.

src/include/nodes/execnodes.h

@@ -3,6 +3,12 @@
  * execnodes.h
  *	  definitions for executor state nodes
  *
+ * ExprState represents the evaluation state for a whole expression tree.
+ * Most Expr-based plan nodes do not have a corresponding expression state
+ * node, they're fully handled within execExpr* - but sometimes the state
+ * needs to be shared with other parts of the executor, as for example
+ * with SubPlanState, which nodeSubplan.c has to modify.
+ *
  *
  * Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California

src/include/nodes/nodes.h

@@ -218,12 +218,6 @@ typedef enum NodeTag
 
 	/*
 	 * TAGS FOR EXPRESSION STATE NODES (execnodes.h)
-	 *
-	 * ExprState represents the evaluation state for a whole expression tree.
-	 * Most Expr-based plan nodes do not have a corresponding expression state
-	 * node, they're fully handled within execExpr* - but sometimes the state
-	 * needs to be shared with other parts of the executor, as for example
-	 * with SubPlanState, which nodeSubplan.c has to modify.
 	 */
 	T_ExprState,
 	T_WindowFuncExprState,