Add language code option

I like this idea and I'm maintainer now. Could someone prepare a MR for review?

Hello ,
I have applied patch #3 on 8.x-1.x and 2.x but it does not apply cleanly.
I have implement the language code by referencing #3 and #5 comment.
Please review the MR.
If any mistake please guide me.
Thanks

I tested the issuse fork and it was successful.

Thanks for the great work on this!

I had a look at the merge request. It looks good, but we are adding a new option to the configuration, so this also needs a config schema update and a simple post-update hook to set the default value for existing installations.

Updated the config schema and provided an update hooks, and did some minor cleanup. I have not tested my changes.

Thanks all, looking really good!

@pfrenssen I might be wrong, but shouldn't "simple" config updates like this use regular update hooks?
See https://www.specbee.com/blogs/update-and-post-update-hooks-for-successfu...

I'm always confused about this. According to the documentation, config updates are supported in hook_update_N(), but I always thought it is best practice to only use those for data model updates nowadays. I saw a bunch of config updates in the post-update hooks of the core system module so I went with that. E.g. system_post_update_service_advisory_settings()

I guess both work. If you want I can change it.

@pfrenssen all good, I'm totally fine with that and I'm also confused, what's the right way ... we can keep it like this.

So only needs final testing?