Seata document (#5560)

* Add: add detail document for seata managed distributed transaction

* Fix: remove duplicated English description

* Refactor: improve the translation as king's suggestion

* Fix: format the document by remove a uesless whitespace

* Refactor: remove another duplicated whitespace

docs/document/content/features/transaction/concept/base-transaction-seata.cn.md

@@ -13,4 +13,12 @@ weight = 3
 `Seata AT`事务模型包含TM(事务管理器)，RM(资源管理器)，TC(事务协调器)。其中TC是一个独立的服务需要单独部署，TM和RM以jar包的方式同业务应用部署在一起，它们同TC建立长连接，在整个事务生命周期内，保持RPC通信。
 其中全局事务的发起方作为TM，全局事务的参与者作为RM ; TM负责全局事务的begin和commit/rollback，RM负责分支事务的执行结果上报，并且通过TC的协调进行commit/rollback。
 
+Seata管理的分布式事务的典型生命周期：
+
+1. TM要求TC开始一个全新的全局事务。TC生成一个代表该全局事务的XID。
+2. XID贯穿于微服务的整个调用链。
+3. 作为该XID对应到的TC下的全局事务的一部分，RM注册了本地事务。
+4. TM要求TC提交或回退XID对应的全局事务。
+5. TC驱动XID对应的全局事务下的所有分支事务完成提交或回退。
+
 ![Seata AT事务模型](https://shardingsphere.apache.org/document/current/img/transaction/seata-at-transaction.png)
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docs/document/content/features/transaction/concept/base-transaction-seata.en.md

@@ -15,4 +15,12 @@ deployed together with business applications in the form of jar packages. They e
 The initiator of global transaction is TM, and the participant of global transaction is RM; TM is in charge of begin and commit/rollback of global transaction, RM is in charge of reporting the 
 execution results of branch transaction, and commit/rollback is executed through TC coordination.
 
+A typical lifecycle of Seata managed distributed transaction:
+
+1. TM asks TC to begin a new global transaction. TC generates an XID representing the global transaction.
+2. XID is propagated through microservices' invoke chain.
+3. RM register local transaction as a branch of the corresponding global transaction of XID to TC.
+4. TM asks TC for committing or rollbacking the corresponding global transaction of XID.
+5. TC drives all branch transactions under the corresponding global transaction of XID to finish branch committing or rollbacking.
+
 ![Seata AT transaction model](https://shardingsphere.apache.org/document/current/img/transaction/seata-at-transaction.png)
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