message: docs: add changelog for 5.2.2
diff: +<a name="5.2.2"></a>
  +## [5.2.2](https://github.com/angular/angular/compare/5.2.1...5.2.2) (2018-01-25)
  +
  +
  +### Bug Fixes
  +
  +* **common:** A null value should remove the style on IE ([#21679](https://github.com/angular/angular/issues/21679)) ([c12ea3a](https://github.com/angular/angular/commit/c12ea3a)), closes [#21064](https://github.com/angular/angular/issues/21064)
  +* **common:** don't remove special characters when extracting CLDR data ([#21626](https://github.com/angular/angular/issues/21626)) ([a62c186](https://github.com/angular/angular/commit/a62c186))
  +* **common:** extract plural function from i18n locale data files for TS 2.6 ([#21626](https://github.com/angular/angular/issues/21626)) ([71f9eaa](https://github.com/angular/angular/commit/71f9eaa)), closes [#21608](https://github.com/angular/angular/issues/21608)
  +* **common:** fallback to last defined value for named date and time formats ([#21299](https://github.com/angular/angular/issues/21299)) ([982eb7b](https://github.com/angular/angular/commit/982eb7b)), closes [#21282](https://github.com/angular/angular/issues/21282)
  +* **compiler:** add support for marker tags in xliff serializers ([#21250](https://github.com/angular/angular/issues/21250)) ([02352bc](https://github.com/angular/angular/commit/02352bc)), closes [#21078](https://github.com/angular/angular/issues/21078)
  +* **compiler:** Don't strip `/*# sourceURL ... */` ([#16088](https://github.com/angular/angular/issues/16088)) ([de6c644](https://github.com/angular/angular/commit/de6c644))
  +* **compiler:** fix ICU select messages to use male/female/other ([#21713](https://github.com/angular/angular/issues/21713)) ([8e44577](https://github.com/angular/angular/commit/8e44577))
  +* **compiler-cli:** do not fold errors past calls in the collector ([#21708](https://github.com/angular/angular/issues/21708)) ([52970c0](https://github.com/angular/angular/commit/52970c0))
  +* **compiler-cli:** do not lower expressions in non-modules ([#21649](https://github.com/angular/angular/issues/21649)) ([ba4ea82](https://github.com/angular/angular/commit/ba4ea82))
  +* **router:** don't use ParamsInheritanceStrategy in declarations ([#21574](https://github.com/angular/angular/issues/21574)) ([8b3fbb5](https://github.com/angular/angular/commit/8b3fbb5)), closes [#21456](https://github.com/angular/angular/issues/21456)
  +
  +
  +
  <a name="6.0.0-beta.0"></a>
  # [6.0.0-beta.0](https://github.com/angular/angular/compare/5.2.0...6.0.0-beta.0) (2018-01-17)
  