Summary:
Standard only-numeric (number pad) keyboard on iOS does not have any "Done" or "Enter" button, and this is often very badly hurt user experience.
Usually it can be solved by implementing custom `inputAccessoryView`, but RN does not have built-in support for customizing it.
So, this commit introduced limited support only for "Done" button (returnKeyType="done") and it should suite very well for the vast majority of use cases.
This is highly requested feature, see more details here:
https://github.com/facebook/react-native/issues/1190
Reviewed By: mmmulani
Differential Revision: D5268020
fbshipit-source-id: 90bd5bffac6aaa1fb7c5c2ac539b35b04d45918f
2b1795c5ad