Codemod $Enum<...> to $Keys<...> in xplat/fbcode

Summary:
In D15367312, I deprecate `$Enum<...>` in favour of `$Keys<...>` (the functionality is identical). Codemod existing usages in xplat and fbcode.

bypass-lint

Reviewed By: samwgoldman

Differential Revision: D15378084

fbshipit-source-id: 251c6b9ac07cb50139a8f03e3a45a5fac0d91812

Libraries/Image/ImageEditor.js

@@ -40,7 +40,7 @@ type ImageCropData = {
    * (Optional) the resizing mode to use when scaling the image. If the
    * `displaySize` param is not specified, this has no effect.
    */
-  resizeMode?: ?$Enum<{
+  resizeMode?: ?$Keys<{
     contain: string,
     cover: string,
     stretch: string,