* MDF [doc] add new tips for local topic remapping feature also

Signed-off-by: jaylin <jaylin@emqx.io>

docs/en_US/config-description/bridges.md

@@ -110,6 +110,17 @@ This configuration enables NanoMQ to establish an MQTT over TCP bridge connectio
 - `subscription`: This is an array of topic objects that need to be subscribed from the remote MQTT server. Each object defines a topic and the QoS level for the subscription(!Be aware that only the first rule takes effect if you configure multiple overlapping rules). Including
   - `remote_topic`: The topic filter used to subscribe to the remote broker.
   - `local_topic`: This is for Topic reflection, if you want the vanila way, then just leave `local_topic=""` to preserve the original topic in msg from remote broker.
+
+  ::: tip
+  
+  `local_topic` of `subscription` section works differently from `forwards` part. In order to ease the work of managing local & remote topic relationship (frequently asked feature from community), since 0.23.7, the topic remapping feature is introduced, which includes the ability to strip or replace parts of the topic with the help of wildcards. Specifically, the wildcard acts as the string searching anchor here for users to preserve the matching parts.
+  For example:
+    `remote_topic = "+/nanomq/#"`
+    `local_topic = "#"`
+    And downward message is from topic `cmd/nanomq/hello/world`, then you get a message with topic `hello/world` locally.
+
+  :::
+
   - `qos`: Define the QoS in the subscribe packet. This is a must. 
   - `retain`: a flag to override retain flag.
   - `retain_as_published`: an optional item for the MQTTv5 feature, Retain As Published.

docs/zh_CN/config-description/bridges.md

@@ -98,7 +98,20 @@ bridges.mqtt.emqx1 = {
   - `certfile`：TLS Cert 证书数据。
   - `cacertfile`：TLS CA 证书数据。
 - `forwards`：转发到远端 MQTT 服务器的主题数组，应包括消息主题（`remote_topic`）、（`local_topic`）和 QoS （`qos`）。
-- `subscription`：需要从远程 MQTT 服务器订阅的主题对象数组，除`forwards`中各项外，还包括以下几项：。
+  - `suffix`：将为远程主题添加后缀字符串（如果 remote_topic 为空，则添加到原始主题）
+  - `prefix`：将为远程主题添加前缀字符串（如果 remote_topic 为空，则添加到原始主题）
+- `subscription`：这是一个需要从远程 MQTT 服务器订阅的主题对象数组。每个对象定义一个主题及其对应的 QoS 级别（请注意，如果配置了多个重叠规则，则只有第一个规则生效）。除`forwards`中各项外，还包括以下几项：
+  - `remote_topic`：用于订阅远程代理的主题过滤器。
+  - `local_topic`：用于主题反射，如果您想要使用原始方式，只需保留 `local_topic=""` 即可，以便在远程代理发送的消息中保留原始主题。
+    ::: tip
+  
+`subscription`部分的`local_topic` 与`forwards`部分的工作方式不同。为了简化管理本地和远程主题关系（社区中经常提及的功能），自 0.23.7 版本起，引入了主题重新映射功能，该功能允许使用通配符删除或替换主题的部分内容。具体来说，通配符在此处充当字符串搜索锚点，以便用户保留匹配的部分。
+例如：
+`remote_topic = "+/nanomq/#"`
+`local_topic = "#"`
+如果下发消息来自主题`cmd/nanomq/hello/world`，则您将收到一条主题为`hello/world`的消息。
+
+  :::
   - `retain`：重载标志位。
   - `retain_as_publish`：MQTTV5可选特性，Retain As Published。
   - `retain_handling`：MQTTV5可选特性，Retain Handling。