Warn against Microsoft <windows.h> min and max macro (#1084)

Warn users they have defined the min/max macros which is not 
compatible with other code from the standard library or FTXUI.

Co-authored-by: Sylko Olzscher <sylko.olzscher@solostec.ch>
Co-authored-by: ArthurSonzogni <sonzogniarthur@gmail.com>

examples/dom/canvas.cpp

@@ -32,10 +32,12 @@ int main() {
 
   // Plot a function:
   std::vector<int> ys(100);
-  for (int x = 0; x < 100; x++)
+  for (int x = 0; x < 100; x++) {
     ys[x] = int(80 + 20 * cos(x * 0.2));
-  for (int x = 0; x < 99; x++)
+  }
+  for (int x = 0; x < 99; x++) {
     c.DrawPointLine(x, ys[x], x + 1, ys[x + 1], Color::Red);
+  }
 
   auto document = canvas(&c) | border;
 

examples/dom/package_manager.cpp

@@ -86,8 +86,9 @@ int main() {
 
   auto render = [&]() {
     std::vector<Element> entries;
-    for (auto& task : displayed_task)
+    for (auto& task : displayed_task) {
       entries.push_back(renderTask(task));
+    }
 
     return vbox({
         // List of tasks.
@@ -138,8 +139,9 @@ int main() {
     std::this_thread::sleep_for(0.01s);
 
     // Exit
-    if (nb_active + nb_queued == 0)
+    if (nb_active + nb_queued == 0) {
       break;
+    }
 
     // Update the model for the next frame.
     updateModel();

examples/dom/spinner.cpp

@@ -21,8 +21,9 @@ int main() {
   for (int index = 0; index < 200; ++index) {
     std::vector<Element> entries;
     for (int i = 0; i < 23; ++i) {
-      if (i != 0)
+      if (i != 0) {
         entries.push_back(separator());
+      }
       entries.push_back(  //
           hbox({
               text(std::to_string(i)) | size(WIDTH, EQUAL, 2),