Rename LOGICAL_REP_MSG_STREAM_END to LOGICAL_REP_MSG_STREAM_STOP.

In the code, most places used the term "Stream Stop" for the logical
stream message. This commit improves consistency by renaming LogicalRepMsgType
"LOGICAL_REP_MSG_STREAM_END" to "LOGICAL_REP_MSG_STREAM_STOP".

Author: Masahiko Sawada
Reviewed-by: Hou Zhijie, Amit Kapila
Discussion: https://postgr.es/m/CAD21AoDeScrsHhLyEPYqN3sydg6PxAPVBboK=30xJfUVihNZDA@mail.gmail.com

src/backend/replication/logical/proto.c

@@ -1074,7 +1074,7 @@ logicalrep_read_stream_start(StringInfo in, bool *first_segment)
 void
 logicalrep_write_stream_stop(StringInfo out)
 {
-	pq_sendbyte(out, LOGICAL_REP_MSG_STREAM_END);
+	pq_sendbyte(out, LOGICAL_REP_MSG_STREAM_STOP);
 }
 
 /*

src/backend/replication/logical/worker.c

@@ -2380,7 +2380,7 @@ apply_dispatch(StringInfo s)
 			apply_handle_stream_start(s);
 			return;
 
-		case LOGICAL_REP_MSG_STREAM_END:
+		case LOGICAL_REP_MSG_STREAM_STOP:
 			apply_handle_stream_stop(s);
 			return;
 

src/include/replication/logicalproto.h

@@ -65,7 +65,7 @@ typedef enum LogicalRepMsgType
 	LOGICAL_REP_MSG_COMMIT_PREPARED = 'K',
 	LOGICAL_REP_MSG_ROLLBACK_PREPARED = 'r',
 	LOGICAL_REP_MSG_STREAM_START = 'S',
-	LOGICAL_REP_MSG_STREAM_END = 'E',
+	LOGICAL_REP_MSG_STREAM_STOP = 'E',
 	LOGICAL_REP_MSG_STREAM_COMMIT = 'c',
 	LOGICAL_REP_MSG_STREAM_ABORT = 'A',
 	LOGICAL_REP_MSG_STREAM_PREPARE = 'p'