Related issue: https://confluence.atlassian.com/confkb/non-ascii-characters-display-as-square-characters-in-confluence-317948797.html
The above problem was occurred in `atlassian/confluence-server:latest`, it's the case 1.
I think the official image should build with all language support (or provided another image tag that with all language support).
I found a way to do that:
```
apt install -y language-selector-common
check-language-support -a | xargs apt install -y
```
I'm not sure it's the best solution but it's solved my problem.
