update description

Author: zhicwu

clickhouse-http-client/src/main/java/com/clickhouse/client/http/config/ClickHouseHttpOption.java

@@ -33,6 +33,10 @@ public enum ClickHouseHttpOption implements ClickHouseOption {
      * Whether to enable keep-alive or not.
      */
     KEEP_ALIVE("http_keep_alive", true, "Whether to use keep-alive or not"),
+    /**
+     * Max open connections apply with Apache HttpClient only.
+     */
+    MAX_OPEN_CONNECTIONS("max_open_connections", 10, "Max open connections apply with Apache HttpClient only."),
     /**
      * Whether to receive information about the progress of a query in response
      * headers.
@@ -47,13 +51,7 @@ public enum ClickHouseHttpOption implements ClickHouseOption {
     /**
      * Web context.
      */
-    WEB_CONTEXT("web_context", "/", "Web context."),
-
-    /**
-     * Max connections of ApacheHttpConnectionImpl
-     */
-    MAX_OPEN_CONNECTIONS("max_open_connections", 10,
-            "max open connections for a ClickHouseConnection");
+    WEB_CONTEXT("web_context", "/", "Web context.");
 
     private final String key;
     private final Serializable defaultValue;