[bug] font issue of og image in Chinese and Japanese language

[JinIgarashi]

When we select Japanese or Chinese language, social image's font has an issue.

• Japanese https://docs.qfield.org/assets/images/social/get-started/concepts.ja.png

• Chinese https://docs.qfield.org/assets/images/social/get-started/concepts.zh.png

According to the documentation, there is a way to set font family in mkdocs.yml, but I am not sure how we can change font family dynamically according to the language of content.

• official document https://squidfunk.github.io/mkdocs-material/setup/setting-up-social-cards/#choosing-a-font