Merge branch 'master' into master

Author: hg-pyun

Diff for: content/community/conferences.md

@@ -22,6 +22,11 @@ December 6, 2019 in Berlin, Germany
 
 [Website](https://reactday.berlin) - [Twitter](https://twitter.com/reactdayberlin) - [Facebook](https://www.facebook.com/reactdayberlin/) - [Videos](https://www.youtube.com/reactdayberlin)
 
+### React Barcamp Cologne 2020 {#react-barcamp-cologne-2020}
+February 1-2, 2020 in Cologne, Germany
+
+[Website](https://react-barcamp.de/) - [Twitter](https://twitter.com/ReactBarcamp) - [Facebook](https://www.facebook.com/reactbarcamp)
+
 ### ReactConf AU 2020 {#reactconfau}
 February 27 & 28, 2020 in Sydney, Australia
 

Diff for: content/community/meetups.md

@@ -61,6 +61,7 @@ Do you have a local React.js meetup? Add it here! (Please keep the list alphabet
 * [Paris](https://www.meetup.com/ReactJS-Paris/)
 
 ## Germany {#germany}
+* [Cologne](https://www.meetup.com/React-Cologne/)
 * [Düsseldorf](https://www.meetup.com/de-DE/ReactJS-Meetup-Dusseldorf/)
 * [Hamburg](https://www.meetup.com/Hamburg-React-js-Meetup/)
 * [Karlsruhe](https://www.meetup.com/react_ka/)

Diff for: content/docs/hooks-reference.md

@@ -449,7 +449,7 @@ function FancyInput(props, ref) {
 FancyInput = forwardRef(FancyInput);
 ```
 
-위의 예제에서 `<FancyInput ref={fancyInputRef} />`를 렌더링한 부모 컴포넌트는 `fancyInputRef.current.focus()`를 호출할 수 있습니다.
+위의 예제에서 `<FancyInput ref={inputRef} />`를 렌더링한 부모 컴포넌트는 `inputRef.current.focus()`를 호출할 수 있습니다.
 
 ### `useLayoutEffect` {#uselayouteffect}