message: Use three backticks for code blocks
diff: @@ -412,7 +412,7 @@ You also need to install MySQL or [MariaDB](https://mariadb.com/downloads).
  Ensure that you are using Python version 3.7 or 3.8, then proceed with:
  -````bash
  +```bash
  # Create a virtual environment and activate it (recommended)
  python3 -m venv venv # setup a python3 virtualenv
  source venv/bin/activate
  @@ -457,7 +457,7 @@ $ make superset
  # Setup pre-commit only
  $ make pre-commit
  -````
  +```
  **Note: the FLASK_APP env var should not need to be set, as it's currently controlled
  via `.flaskenv`, however if needed, it should be set to `superset.app:create_app()`**
  