`metadata.default_lang` is reversed

[UltCombo]

Why is the default_lang metadata property representing the opposite of whether the post is in the default lang? Any ideas, @jaydson?

Fixing this will break all existing themes that rely on it. I propose adding a new property, metadata.isDefaultLang implementing the correct behavior, and deprecate or outright remove metadata.default_lang.

What do you guys think?

[jaydson]

I think this default_lang was used to check if there's a default lang, not to check if the post is the default lang. Perhaps it can be changed and there's no need for it anymore.