documented content length arguments in standalone server

Author: dreamhead

moco-doc/ReleaseNotes.md

@@ -1,5 +1,8 @@
 # Release
 
+## CLI
+* add `--content-length` for max request content length in standalone server
+
 ## JUnit 5
 * HTTP and HTTPS with JSON configuration from file/class path
 

moco-doc/cmd.md

@@ -117,6 +117,12 @@ If you don't want see too many logs, you could make the server quiet with `-q` o
 java -jar moco-runner-<version>-standalone.jar http -p 12306 -c foo.json -q
 ```
 
+## Max Content Length
+Max content length for a single request is set by default, but it is not enough for some case. You can set your own content length with content-length arguments.
+```shell
+java -jar moco-runner-<version>-standalone.jar http -p 12306 -c foo.json --content-length 2097152
+```
+
 ## Version
 
 You can query Moco version by the following command: 
@@ -155,4 +161,4 @@ Then you can use the shutdown port to shutdown the running Moco instance.
 
 ```shell
 java -jar moco-runner-<version>-standalone.jar shutdown -s 9527
-```
+```