1. Copy en.json to a new json file named <lang>.json, and translate all the items inside. The language should match what is available in Obsidian app.
2. Modify the index.ts file to include the new language file.

## Why Seperated Repo?

For better pull requests management.

It's actually harder to manage pull requests of submodule for me. The submodule is merged back to the main repo on 20240106. Any further improved translations (and/or pull requestes) should be dealt with in the main repo.