Add support for nxxm.

[nxxm](https://nxxm.github.io)

src/ftxui/dom/blink.cpp

@@ -0,0 +1,25 @@
+#include "ftxui/dom/node_decorator.hpp"
+#include "ftxui/dom/elements.hpp"
+
+namespace ftxui {
+
+class Blink : public NodeDecorator {
+ public:
+  Blink(Elements children) : NodeDecorator(std::move(children)) {}
+  ~Blink() override {}
+
+  void Render(Screen& screen) override {
+    Node::Render(screen);
+    for (int y = box_.y_min; y <= box_.y_max; ++y) {
+      for (int x = box_.x_min; x <= box_.x_max; ++x) {
+        screen.PixelAt(x, y).blink = true;
+      }
+    }
+  }
+};
+
+std::unique_ptr<Node> blink(Element child) {
+  return std::make_unique<Blink>(unpack(std::move(child)));
+}
+
+};  // namespace ftxui