[feature] color indented code blocks

[vepain]

It would be great to color code blocks when they are indented.

Indented code blocks appear under items of ordered lists to respect markdown lint conventions md029

Exemple:

1. Clone from GitHub

    ```sh
    git clone [email protected]:myrepo.git
    cd myrepo
    ```

2. *(Recommended)* install the package in a virtual environment.

    ```sh
    python3.10 -m pip install virtualenv
    python3.10 -m virtualenv .venv310
    source .venv310/bin/activate
    ```

[mjbvz]

Seems to work fine for me with other languages besides shell:

[vepain]

Thank you for your example.
The behaviour is not the same for shell: