title: Regenerate sources when AdditionalFiles content changed in IncrementalSourceGenerator
body: <p>I would like to know is it possible somehow to regenerate sources in IncrementalSourceGenerator when content of AdditionalFiles changed?</p>
  <p>I need to regenerate sources in realtime when user will change additional files, but for now I can do this only when I build or re-build project.</p>
  <p>I know that MAUI is uodated to IncrementalSourceGenerator and I would like to know how they subscribed to AdditionalFiles changes in generator.
  Or does this actually possible?</p>