README: mention $NVR_CMD

README.rst

@@ -28,14 +28,18 @@ Intro
 
 **nvr** is a tool that helps controlling nvim processes.
 
-It basically does two things:
+It does two things:
 
 1. adds back the ``--remote`` family of options (see ``man vim``)
 2. helps controlling the current nvim from within ``:terminal``
 
-To target a certain nvim process, you either use the ``--servername``
+To target a specific nvim process, use either the ``--servername``
 option or set the environment variable ``$NVIM_LISTEN_ADDRESS``.
 
+If the targeted address does not exist, nvr starts a new process on its
+own by running "nvim". You can change the command by setting
+``$NVR_CMD``.
+
 Since ``$NVIM_LISTEN_ADDRESS`` is implicitely set by each nvim process,
 you can call **nvr** from within Neovim (``:terminal``) without
 specifying ``--servername``.