message: Update docs for bundle usage
diff: @@ -27,7 +27,9 @@ import Box from '@primer/components/lib/Box'
  import Flex from '@primer/components/lib/Flex'
  ```
  -Importing components individually can reduce bundle sizes if you don't have tree-shaking set up in your app.
  +Note that the files in the `lib` folder are CommonJS-style modules; if you're using ECMAScript modules (ESM) and a compatible module bundler, importing files from `lib` provides no benefit, as unused modules from the ESM build will be removed via tree-shaking. Primer Components has an ESM build specified in its `package.json`, so when using ESM you should always import components from the main entry point (as in the first example, above).
  +
  +If you're *not* using ESM, importing components individually from the `lib` folder may drastically decrease your final bundle size, since your module bundler will not have to include the entirety of Primer Components in your bundle.
  ### Peer dependencies
  