Fix outdated close handshake docs

Closes #212

Author: nhooyr

close_notjs.go

@@ -84,7 +84,7 @@ func (c *Conn) writeClose(code StatusCode, reason string) error {
 func (c *Conn) waitCloseHandshake() error {
 	defer c.close(nil)
 
-	ctx, cancel := context.WithTimeout(context.Background(), time.Second*10)
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
 	defer cancel()
 
 	err := c.readMu.lock(ctx)