Can not find jsonNodeReader_en.properties

[woojoo520]

Hi team, first really thanks for your contribution to this project.
While analyzing my own project's performance though JFR, I discovered some exceptions were being generator when validating json schema. We found the exceptions were occurring during the execution of the following code:
https://github.com/fge/msg-simple/blob/master/src/main/java/com/github/fge/msgsimple/provider/LoadingMessageSourceProvider.java#L202

Here is the exception info (the locale can be "" / "en" / "en_CN"):
java.util.concurrent.FutureTask@xxx[Completed exceptionally: java.io.IOException: resource "/com/github/fge/jsonschema/core/core_en_CN.properties" not found]
java.util.concurrent.FutureTask@xxx[Completed exceptionally: java.io.IOException: resource "/com/github/fge/jackson/jsonNodeReader_en.properties" not found]

Although these exceptions were ignored, our service is unware of it. Since exceptions are much more time-consuming compared to regular code execution, we attempted to pinpoint this issue.

Again, thanks for your work! If you have any suggestions, please feel free to contact me :)