Wiki: add documentation for 'localizedDates'

[tomtjes]

I can't figure out how to contribute to the Wiki (the given instructions don't work), so here is a proposed change.

File: 🎌-Languages.md

append:

## Localizing Dates
To use translated names of months and days of the week, simply add:

```toml
[params]
localizedDates = true
```