Use Enums for logical replication message types at more places.

Commit 644f0d7cc9 added logical replication message type enums to use
instead of character literals but some char substitutions were overlooked.

Author: Peter Smith
Reviewed-by: Amit Kapila
Discussion: https://postgr.es/m/CAHut+PsTG=Vrv8hgrvOnAvCNR21jhqMdPk2n0a1uJPoW0p+UfQ@mail.gmail.com

src/backend/replication/logical/worker.c

@@ -304,7 +304,7 @@ ensure_transaction(void)
  * Returns true for streamed transactions, false otherwise (regular mode).
  */
 static bool
-handle_streamed_transaction(const char action, StringInfo s)
+handle_streamed_transaction(LogicalRepMsgType action, StringInfo s)
 {
 	TransactionId xid;
 
@@ -1090,7 +1090,7 @@ apply_handle_relation(StringInfo s)
 {
 	LogicalRepRelation *rel;
 
-	if (handle_streamed_transaction('R', s))
+	if (handle_streamed_transaction(LOGICAL_REP_MSG_RELATION, s))
 		return;
 
 	rel = logicalrep_read_rel(s);
@@ -1108,7 +1108,7 @@ apply_handle_type(StringInfo s)
 {
 	LogicalRepTyp typ;
 
-	if (handle_streamed_transaction('Y', s))
+	if (handle_streamed_transaction(LOGICAL_REP_MSG_TYPE, s))
 		return;
 
 	logicalrep_read_typ(s, &typ);
@@ -1148,7 +1148,7 @@ apply_handle_insert(StringInfo s)
 	TupleTableSlot *remoteslot;
 	MemoryContext oldctx;
 
-	if (handle_streamed_transaction('I', s))
+	if (handle_streamed_transaction(LOGICAL_REP_MSG_INSERT, s))
 		return;
 
 	ensure_transaction();
@@ -1269,7 +1269,7 @@ apply_handle_update(StringInfo s)
 	RangeTblEntry *target_rte;
 	MemoryContext oldctx;
 
-	if (handle_streamed_transaction('U', s))
+	if (handle_streamed_transaction(LOGICAL_REP_MSG_UPDATE, s))
 		return;
 
 	ensure_transaction();
@@ -1426,7 +1426,7 @@ apply_handle_delete(StringInfo s)
 	TupleTableSlot *remoteslot;
 	MemoryContext oldctx;
 
-	if (handle_streamed_transaction('D', s))
+	if (handle_streamed_transaction(LOGICAL_REP_MSG_DELETE, s))
 		return;
 
 	ensure_transaction();
@@ -1795,7 +1795,7 @@ apply_handle_truncate(StringInfo s)
 	List	   *relids_logged = NIL;
 	ListCell   *lc;
 
-	if (handle_streamed_transaction('T', s))
+	if (handle_streamed_transaction(LOGICAL_REP_MSG_TRUNCATE, s))
 		return;
 
 	ensure_transaction();