Remove default value from description

Resolves #1693

Author: patiencedaur

doc/book/replication/repl_monitoring.rst

@@ -55,10 +55,10 @@ The primary indicators of replication health are:
 *   :ref:`idle <box_info_replication_upstream_idle>`, the time (in seconds) since
     the instance received the last event from a master.
 
-    A master sends heartbeat messages to a replica every second, and the master
+    If the master has no updates to send to the replicas, it sends heartbeat messages
+    every :ref:`replication_timeout <cfg_replication-replication_timeout>` seconds. The master
     is programmed to disconnect if it does not see acknowledgments of the heartbeat messages
-    within :ref:`replication_timeout <cfg_replication-replication_timeout>` * 4
-    seconds.
+    within ``replication_timeout`` * 4 seconds.
 
     Therefore, in a healthy replication setup, ``idle`` should never exceed
     ``replication_timeout``: if it does, either the replication is lagging

locale/ru/LC_MESSAGES/book/replication/repl_monitoring.po

@@ -100,15 +100,16 @@ msgstr ""
 "с момента получения последнего события от мастера."
 
 msgid ""
-"A master sends heartbeat messages to a replica every second, and the master "
+"If the master has no updates to send to the replicas, it sends heartbeat messages "
+"every ``replication_timeout`` seconds. The master "
 "is programmed to disconnect if it does not see acknowledgments of the "
 "heartbeat messages within :ref:`replication_timeout <cfg_replication-"
 "replication_timeout>` * 4 seconds."
 msgstr ""
-"Мастер отправляет сообщения контрольного сигнала на реплику каждую секунду, "
-"и мастер запрограммирован на отключение, если он не получает сообщения "
-"контрольного сигнала дольше :ref:`replication_timeout <cfg_replication-"
-"replication_timeout>` * 4 секунд."
+"Если на мастере нет новых данных, требующих репликации, он отправляет на реплики "
+"сообщения контрольного сигнала каждые :ref:`replication_timeout <cfg_replication-replication_timeout>` секунд. "
+"Мастер запрограммирован на отключение, если он не получает сообщения "
+"контрольного сигнала дольше ``replication_timeout`` * 4 секунд."
 
 msgid ""
 "Therefore, in a healthy replication setup, ``idle`` should never exceed "