doc wording fix

Author: felicienfrancois

README.md

@@ -115,8 +115,8 @@ __Arguments__
   * sslCaDir - Path to the certificates cache directory (default: process.cwd() + '/.http-mitm-proxy')
   * silent - if set to true, nothing will be written to console (default: false)
   * timeout - The number of milliseconds of inactivity before a socket is presumed to have timed out. Defaults to no timeout.
-  * httpAgent - The [http.Agent](https://nodejs.org/api/http.html#http_class_http_agent) to use when making http requests. Useful for chaining proxys. Defaults to an internal Agent.
-  * httpsAgent - The [https.Agent](https://nodejs.org/api/https.html#https_class_https_agent) to use when making https requests. Useful for chaining proxys. Defaults to an internal Agent.
+  * httpAgent - The [http.Agent](https://nodejs.org/api/http.html#http_class_http_agent) to use when making http requests. Useful for chaining proxys. (default: internal Agent)
+  * httpsAgent - The [https.Agent](https://nodejs.org/api/https.html#https_class_https_agent) to use when making https requests. Useful for chaining proxys. (default: internal Agent)
   * forceSNI - force use of [SNI](https://en.wikipedia.org/wiki/Server_Name_Indication) by the client. Allow node-http-mitm-proxy to handle all HTTPS requests with a single internal server.
 
 __Example__