message: docs: release notes for the v9.1.0 release
diff: +<a name="9.1.0"></a>
  +# [9.1.0](https://github.com/angular/angular/compare/9.1.0-rc.2...9.1.0) (2020-03-25)
  +
  +Promoted `9.1.0-rc.2` to `9.1.0`.
  +
  +
  <a name="9.1.0-rc.2"></a>
  # [9.1.0-rc.2](https://github.com/angular/angular/compare/9.1.0-rc.1...9.1.0-rc.2) (2020-03-24)
  