Build from Source: add missing paren in publishing (facebook#3387)

Author: Peter Cho

website/contributing/how-to-build-from-source.md

@@ -162,7 +162,7 @@ Gradle build fails in `ndk-build`. See the section about `local.properties` file
 
 ## Publish your own version of React Native
 
-There is a docker image that helps you build the required Android sources without installing any additional tooling (other than [Docker](https://docs.docker.com/install/), which can be committed to a git branch as a fully functional React Native fork release.
+There is a docker image that helps you build the required Android sources without installing any additional tooling (other than [Docker](https://docs.docker.com/install/)), which can be committed to a git branch as a fully functional React Native fork release.
 
 Run this from a fork of the React Native [repo](https://github.com/facebook/react-native).