We had a few alerts in the D-Bus tutorial that lacked the color setting, making alerts unreadable:

![Screenshot_20240818_234548](/uploads/3cb6015f7ceb47193552f8ffa5cbb709/Screenshot_20240818_234548.webp)

I also added a few newlines for those alerts, following https://develop.kde.org/docs/contribute/formatting/#add-a-line-between-shortcodes