docs: add rsbuild-plugin-i18next-extractor to Known-plugins section (#153)

Author: luhc228

README.md

@@ -1102,6 +1102,7 @@ This programmatic API gives you the same power as the CLI but with full control
 ## Known plugins
 
 - [i18next-cli-plugin-svelte](https://github.com/dreamscached/i18next-cli-plugin-svelte) — a simple plugin to extract translation keys from Svelte components
+[rsbuild-plugin-i18next-extractor](https://github.com/rspack-contrib/rsbuild-plugin-i18next-extractor) — A Rsbuild plugin that leverages the Rspack module graph to extract only the i18n translations that are actually imported and used in your code, preventing unused translations from being bundled.
 
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