adding line breaker

lectures/02_strings_vectors/README.md

@@ -49,6 +49,7 @@ where h is as defined above.
   – It can be treated like an ordinary array using the subscripting operator.  
   – A vector knows how many elements it stores! (unlike C arrays)  
   – There is NO automatic checking of subscript bounds.  
+
  Here’s how we create an empty vector of integers:
 ```cpp
 std::vector<int> scores;