docs: Add missing API ref docs for Docusaurus Faster options (#10630)

Author: slorber

website/docs/api/docusaurus.config.js.mdx

@@ -200,6 +200,10 @@ export default {
     experimental_faster: {
       swcJsLoader: true,
       swcJsMinimizer: true,
+      swcHtmlMinimizer: true,
+      lightningCssMinimizer: true,
+      rspackBundler: true,
+      mdxCrossCompilerCache: true,
     },
     experimental_storage: {
       type: 'localStorage',
@@ -210,9 +214,13 @@ export default {
 };
 ```
 
-- `experimental_faster`: An object containing feature flags to make the Docusaurus build faster. This requires adding the `@docusaurus/faster` package to your site's dependencies. Use `true` as a shorthand to enable all flags.
-  - `swcJsLoader`: Use `true` to replace the default [Babel](https://babeljs.io/) JS loader by the [SWC](https://swc.rs/) JS loader to speed up the bundling phase.
-  - `swcJsMinimizer`: Use `true` to replace the default [`terser-webpack-plugin`](https://github.com/webpack-contrib/terser-webpack-plugin) JS minimizer ([Terser](https://terser.org/)) by the [SWC JS minimizer](https://swc.rs/docs/configuration/minification) to speed up the bundling minification phase.
+- `experimental_faster`: An object containing feature flags to make the Docusaurus build faster. This requires adding the `@docusaurus/faster` package to your site's dependencies. Use `true` as a shorthand to enable all flags. Read more on the [Docusaurus Faster](https://github.com/facebook/docusaurus/issues/10556) issue. Available feature flags:
+  - [`swcJsLoader`](https://github.com/facebook/docusaurus/pull/10435): Use [SWC](https://swc.rs/) to transpile JS (instead of [Babel](https://babeljs.io/)).
+  - [`swcJsMinimizer`](https://github.com/facebook/docusaurus/pull/10441): Use [SWC](https://swc.rs/) to minify JS (instead of [Terser](https://github.com/terser/terser)).
+  - [`swcHtmlMinimizer `](https://github.com/facebook/docusaurus/pull/10554): Use [SWC](https://swc.rs/) to minify HTML and inlined JS/CSS (instead of [html-minifier-terser](https://github.com/terser/html-minifier-terser)).
+  - [`lightningCssMinimizer`](https://github.com/facebook/docusaurus/pull/10522): Use [Lightning CSS](https://lightningcss.dev/) to minify CSS (instead of [cssnano](https://github.com/cssnano/cssnano) and [clean-css](https://github.com/clean-css/clean-css)).
+  - [`rspackBundler`](https://github.com/facebook/docusaurus/pull/10402): Use [Rspack](https://rspack.dev/) to bundle your app (instead of [webpack](https://webpack.js.org/)).
+  - [`mdxCrossCompilerCache`](https://github.com/facebook/docusaurus/pull/10479): Compile MDX files only once for both browser/Node.js environments instead of twice.
 - `experimental_storage`: Site-wide browser storage options that theme authors should strive to respect.
   - `type`: The browser storage theme authors should use. Possible values are `localStorage` and `sessionStorage`. Defaults to `localStorage`.
   - `namespace`: Whether to namespace the browser storage keys to avoid storage key conflicts when Docusaurus sites are hosted under the same domain, or on localhost. Possible values are `string | boolean`. The namespace is appended at the end of the storage keys `key-namespace`. Use `true` to automatically generate a random namespace from your site `url + baseUrl`. Defaults to `false` (no namespace, historical behavior).