Allow users to provide their own lang.toml file

[Zurga]

Love the template, it is much faster then the Latex equivalent.

I would like to be able to provide my own lang.toml file for more customization. I think this would be possible if we allow the user to set this in the dictionaries passed to the coverletter and resume functions. Something like: lang-file: mylang.toml.

Edit: I managed to get it working by symlinking my lang.toml in ~/.cache/typst/packages/preview/modern-cv/. I put this here in case someone else needs a quick fix.