wutui: missing newline disfigures terminal on exit

**Reproduce**
1. Open a terminal session
2. Run `wutui`
3. Press `q` to quit

**What happens**
The login prompt is on the right of the screen, where the `wutui` drawing ended.

**What was expected**
The login prompt appears as a new line, starting on the left of the screen.

**Supposed cause**
Probably missing printing a newline character on exit.