enh: refactor error msgs, i.e. Sync not leader and Sync is restoring

source/util/src/terror.c

@@ -412,7 +412,7 @@ TAOS_DEFINE_ERROR(TSDB_CODE_GRANT_TABLE_LIMITED,          "Table creation limite
 // sync
 TAOS_DEFINE_ERROR(TSDB_CODE_SYN_TIMEOUT,                  "Sync timeout")
 TAOS_DEFINE_ERROR(TSDB_CODE_SYN_IS_LEADER,                "Sync is leader")
-TAOS_DEFINE_ERROR(TSDB_CODE_SYN_NOT_LEADER,               "Sync not leader")
+TAOS_DEFINE_ERROR(TSDB_CODE_SYN_NOT_LEADER,               "Sync leader is unreachable")
 TAOS_DEFINE_ERROR(TSDB_CODE_SYN_ONE_REPLICA,              "Sync one replica")
 TAOS_DEFINE_ERROR(TSDB_CODE_SYN_NOT_IN_NEW_CONFIG,        "Sync not in new config")
 TAOS_DEFINE_ERROR(TSDB_CODE_SYN_NEW_CONFIG_ERROR,         "Sync new config error")
@@ -420,7 +420,7 @@ TAOS_DEFINE_ERROR(TSDB_CODE_SYN_RECONFIG_NOT_READY,       "Sync not ready for re
 TAOS_DEFINE_ERROR(TSDB_CODE_SYN_PROPOSE_NOT_READY,        "Sync not ready for propose")
 TAOS_DEFINE_ERROR(TSDB_CODE_SYN_STANDBY_NOT_READY,        "Sync not ready for standby")
 TAOS_DEFINE_ERROR(TSDB_CODE_SYN_BATCH_ERROR,              "Sync batch error")
-TAOS_DEFINE_ERROR(TSDB_CODE_SYN_RESTORING,                "Sync is restoring")
+TAOS_DEFINE_ERROR(TSDB_CODE_SYN_RESTORING,                "Sync leader is restoring")
 TAOS_DEFINE_ERROR(TSDB_CODE_SYN_INVALID_SNAPSHOT_MSG,     "Sync invalid snapshot msg")
 TAOS_DEFINE_ERROR(TSDB_CODE_SYN_BUFFER_FULL,              "Sync buffer is full")
 TAOS_DEFINE_ERROR(TSDB_CODE_SYN_INTERNAL_ERROR,           "Sync internal error")