chore: add contributing docs guide

README.md

@@ -24,3 +24,20 @@ See the [docs](https://test-utils.vuejs.org/).
 ## Development
 
 Get started by running `pnpm install`. You can run the tests with `pnpm test`. That's it!
+
+## Contributing Docs
+
+All the documentation files can be found in `packages/docs`. It contains the English markdown files while translation(s) are stored in their corresponding `<lang>` sub-folder(s):
+
+- [`fr`](https://github.com/vuejs/test-utils/tree/main/packages/docs/fr): French translation.
+
+Besides that, the `.vitepress` sub-folder contains the config and theme, including the i18n information.
+
+- `pnpm docs:dev`: Start the docs dev server.
+- `pnpm docs:build`: Build the docs.
+
+To add or maintain the translations, we follow the [Vue Ecosystem Translation Guidelines](https://github.com/vuejs-translations/guidelines/blob/main/README_ECOSYSTEM.md).
+
+- `pnpm docs:translation:status [<lang>]`: Show the translation status for your language. If you don't specify a language, it will show the status for all languages.
+- `pnpm docs:translation:compare <lang>`: Compare the docs with the latest checkpoint for your language.
+- `pnpm docs:translation:update <lang> [<commit>]`: Update the checkpoint for your language. The checkpoint will be set by the latest commit hash. However, you can also specify a commit hash manually.