Add missing keys to default langage

[lfabreges]

en.default.json

{
  "app.name": "Example"
}

fr.default.json

{
  "Hello World !": "Bonjour le monde !"
}

Problem

I don't need to add the `Hello World !" key to the default langage as it is already in english. This will lead to a lint error when building the release build for Android.

Solution

What I'll do is add all the missing keys in the default langage too, at the end, it will be as if you had defined the default langage like this:

{
  "app.name": "Example",
  "Hello World !": "Hello World !"
}