Summary:
The documentation for `KeyboardAvoidingView` was pretty thin. Tried to fill it out more and corrected a couple words.
n/a
[DOCS] [ENHANCEMENT] [KeyboardAvoidingView] - Improve the documentation for the props for KeyboardAvoidingView
* **Who does this affect**: Users that are manually calling the methods on KeyboardingAvoidingView.
* **How to migrate**: Add an underscore before the name of the method
* **Why make this breaking change**: These methods are not meant to be public. For example, the exposed `onLayout` function is not a prop that accepts a function like is typical of the rest of React Native but is the internal method that is called when the component's onLayout is triggered.
* **Severity (number of people affected x effort)**: Low
Closes https://github.com/facebook/react-native/pull/16479
Differential Revision: D6261005
Pulled By: hramos
fbshipit-source-id: 7e0bcfb0e7cb6bb419964bd0b02cf52c9347c608