Add missing enum tags in enums used in nodes

Discussion: https://www.postgresql.org/message-id/flat/c1097590-a6a4-486a-64b1-e1f9cc0533ce@enterprisedb.com

src/include/nodes/parsenodes.h

@@ -1337,7 +1337,7 @@ typedef struct SortGroupClause
  *
  * SETS( SIMPLE(1,2), CUBE( SIMPLE(3), SIMPLE(4,5) ) )
  */
-typedef enum
+typedef enum GroupingSetKind
 {
 	GROUPING_SET_EMPTY,
 	GROUPING_SET_SIMPLE,
@@ -2124,7 +2124,7 @@ typedef struct CopyStmt
  * preserve the distinction in VariableSetKind for CreateCommandTag().
  * ----------------------
  */
-typedef enum
+typedef enum VariableSetKind
 {
 	VAR_SET_VALUE,				/* SET var = value */
 	VAR_SET_DEFAULT,			/* SET var TO DEFAULT */

src/include/nodes/pathnodes.h

@@ -1525,7 +1525,7 @@ typedef struct MemoizePath
  * it's convenient to have a UniquePath in the path tree to signal upper-level
  * routines that the input is known distinct.)
  */
-typedef enum
+typedef enum UniquePathMethod
 {
 	UNIQUE_PATH_NOOP,			/* input is known unique already */
 	UNIQUE_PATH_HASH,			/* use hashing */

src/include/nodes/primnodes.h

@@ -1215,7 +1215,7 @@ typedef enum XmlExprOp
 	IS_DOCUMENT					/* xmlval IS DOCUMENT */
 } XmlExprOp;
 
-typedef enum
+typedef enum XmlOptionType
 {
 	XMLOPTION_DOCUMENT,
 	XMLOPTION_CONTENT