no protocol usage inprove docs

Signed-off-by: Andy Green <andy.green@linaro.org>

lib/client-handshake.c

@@ -284,7 +284,8 @@ failed:
  * @origin:	Socket origin name
  * @protocol:	Comma-separated list of protocols being asked for from
  *		the server, or just one.  The server will pick the one it
- *		likes best.
+ *		likes best.  If you don't want to specify a protocol, which is
+ *		legal, use NULL here.
  * @ietf_version_or_minus_one: -1 to ask to connect using the default, latest
  *		protocol supported, or the specific protocol ordinal
  *

lib/libwebsockets.h

@@ -839,7 +839,7 @@ typedef int (extension_callback_function)(struct libwebsocket_context *context,
  * struct libwebsocket_protocols -	List of protocols and handlers server
  *					supports.
  * @name:	Protocol name that must match the one given in the client
- *		Javascript new WebSocket(url, 'protocol') name
+ *		Javascript new WebSocket(url, 'protocol') name.
  * @callback:	The service callback used for this protocol.  It allows the
  *		service action for an entire protocol to be encapsulated in
  *		the protocol-specific callback
@@ -870,6 +870,10 @@ typedef int (extension_callback_function)(struct libwebsocket_context *context,
  *	This structure represents one protocol supported by the server.  An
  *	array of these structures is passed to libwebsocket_create_server()
  *	allows as many protocols as you like to be handled by one server.
+ *
+ *	The first protocol given has its callback used for user callbacks when
+ *	there is no agreed protocol name, that's true during HTTP part of the
+ *	connection and true if the client did not send a Protocol: header.
  */
 
 struct libwebsocket_protocols {