docs: improve descriptions

Thanks to @qzhuyan for the corrections

apps/emqx_connector/i18n/emqx_connector_mongo.conf

@@ -109,7 +109,7 @@ The MongoDB default port 27017 is used if `[:Port]` is not specified.
     overflow_ttl {
       desc {
         en: "Period of time before workers that exceed the configured pool size (\"overflow\") to be terminated."
-        zh: "超过配置的池子大小（\"溢出\"）的工人被终止前的时间段。"
+        zh: "当池内工人太多时，等待多久清除多余工人。"
       }
       label {
         en: "Overflow TTL"
@@ -124,7 +124,7 @@ The MongoDB default port 27017 is used if `[:Port]` is not specified.
       }
       label {
         en: "Overflow Check Period"
-        zh: "溢出检查期"
+        zh: "溢出检查周期"
       }
     }
 
@@ -142,7 +142,7 @@ The MongoDB default port 27017 is used if `[:Port]` is not specified.
     connect_timeout {
       desc {
         en: "The duration to attempt a connection before timing out."
-        zh: "在超时前尝试连接的持续时间。"
+        zh: "超时重连的等待时间。"
       }
       label {
         en: "Connect Timeout"
@@ -157,7 +157,7 @@ The MongoDB default port 27017 is used if `[:Port]` is not specified.
       }
       label {
         en: "Socket Timeout"
-        zh: "插座超时"
+        zh: "套接字操作超时"
       }
     }
 
@@ -197,7 +197,7 @@ The MongoDB default port 27017 is used if `[:Port]` is not specified.
     min_heartbeat_period {
       desc {
         en: "Controls the minimum amount of time to wait between heartbeats."
-        zh: "控制心跳之间的最小等待时间。"
+        zh: "心跳间的最小间隙"
       }
       label {
         en: "Minimum Heartbeat Period"