Update How-To-Emit-YAML.md (#976)

docs/How-To-Emit-YAML.md

@@ -155,15 +155,9 @@ produces
 We overload `operator <<` for `std::vector`, `std::list`, and `std::map`, so you can write stuff like:
 
 ```cpp
-std::vector <int> squares;
-squares.push_back(1);
-squares.push_back(4);
-squares.push_back(9);
-squares.push_back(16);
-
-std::map <std::string, int> ages;
-ages["Daniel"] = 26;
-ages["Jesse"] = 24;
+std::vector <int> squares = {1, 4, 9, 16};
+
+std::map <std::string, int> ages = {{"Daniel", 26}, {"Jesse", 24}};
 
 YAML::Emitter out;
 out << YAML::BeginSeq;