message: docs: update Roadmap section header from "Done" to "Completed"
  "Completed" just sounds better (to me).
  PR Close
diff: @@ -4,7 +4,7 @@ Angular receives a large number of feature requests, both from inside Google and
  The projects below are not associated with a particular Angular version. We'll release them on completion, and they will be part of a specific version based on our release schedule, following semantic versioning. For example, features are released in the next minor after they are complete, or the next major if they include breaking changes.
  -## In Progress
  +## In progress
  ### Improve test times and debugging with automatic test environment tear down
  @@ -82,7 +82,7 @@ A common problem with web applications is their slow initial load time. A way to
  <details class="completed-details" open="true">
  <summary>
  - <h2>Done</h2>
  + <h2>Completed</h2>
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