docs: add changelog for 5.2.2

Author: mhevery

CHANGELOG.md

@@ -1,3 +1,22 @@
+<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)