message: Fix formatting in coding style doc.
diff: @@ -85,6 +85,7 @@ If an interface has data member, it's no longer abstract. Derived classes can't
  // ...
  }
  ```
  +
  1. Usage of "Non-null assertion operator" in the code. Don't use it when declaring members which are not initialized (if needed use optional operator instead: ?)
  ```typescript
  