remove outdated info

Author: qbig

docs/KnownIssues.md

@@ -46,7 +46,6 @@ There are properties that work on one platform only, either because they can inh
 There are known cases where the APIs could be made more consistent across iOS and Android:
 
 - `<AndroidViewPager>` and `<ScrollView pagingEnabled={true}>` on iOS do a similar thing. We might want to unify them to `<ViewPager>`.
-- `alert()` needs Android support (once the Dialogs module is open sourced)
 - It might be possible to bring `LinkingIOS` and `IntentAndroid` closer together.
 - `ActivityIndicator` could render a native spinning indicator on both platforms (currently this is done using `ActivityIndicatorIOS` on iOS and `ProgressBarAndroid` on Android).
 - `ProgressBar` could render a horizontal progress bar on both platforms (on iOS this is `ProgressViewIOS`, on Android it's `ProgressBarAndroid`).