DOC: httpclient/lua: fix the type of the dst parameter

"dst" is of string type.
diff --git a/doc/lua-api/index.rst b/doc/lua-api/index.rst
index f22fac3..e87ca07 100644
--- a/doc/lua-api/index.rst
+++ b/doc/lua-api/index.rst
@@ -1869,7 +1869,7 @@
   :param string request.url: Is a mandatory parameter for the request that contains the URL.
   :param string request.body: Is an optional parameter for the request that contains the body to send.
   :param table request.headers: Is an optional parameter for the request that contains the headers to send.
-  :param table request.dst: Is an optional parameter for the destination in haproxy address format.
+  :param string request.dst: Is an optional parameter for the destination in haproxy address format.
   :param integer request.timeout: Optional timeout parameter, set a "timeout server" on the connections.
   :returns: Lua table containing the response