[Bug] Error message in console due to rewritten language selection

**URL**
https://jamulus.io

**Describe the bug**
https://github.com/jamulussoftware/jamuluswebsite/blob/2c40eecf03baab55a8cf4a6bbd09a73acf68db6e/_includes/footer.html#L27-L41 does not find suglang as the respective code has been removed (if we use the "new" language selector)

We should have a way to still mark suggested languages somehow.

@ignotus666

Start with _includes/footer.html lines 27-41 and inspect how the rewritten language selector handles suggested languages. Confirm how the new selector represents language codes, then preserve the suggested-language marking without the console error; verify the selector still works at https://jamulus.io.

Written by the indexing model from the issue text.