message: Fix TabHeading reference to point to right type
diff: @@ -631,7 +631,7 @@ declare module "native-base" {
  }
  interface Tab {
  - heading: TabHeading;
  + heading: _TabHeading;
  }
  interface TabHeading {
  activeTabStyle?: ReactNative.ViewStyle;
  @@ -909,6 +909,7 @@ declare module "native-base" {
  export class Tab extends React.Component<NativeBase.Tab, any> {}
  export class TabHeading extends React.Component<NativeBase.TabHeading, any> {}
  + type _TabHeading = TabHeading;
  /**
  * NativeBase.Item
  */
  