fix some warnings (#660)

Co-authored-by: ArthurSonzogni <sonzogniarthur@gmail.com>

examples/component/resizable_split.cpp

@@ -8,7 +8,7 @@
 
 using namespace ftxui;
 
-int main(int argc, const char* argv[]) {
+int main() {
   auto screen = ScreenInteractive::Fullscreen();
 
   auto middle = Renderer([] { return text("middle") | center; });