Allow languages to support multiple suffixes

[psirenny]

It's common for languages to use multiple file extensions. For example, the C language supports .c and .h files. JavaScript supports .cjs, .mjs, and .js files, and so on. I propose we modify Janus to support multiple suffixes to ease translation.

See the line for a list of languages and their suffixes:
https://github.com/spear-ai/janus-llm/blob/public/janus/utils/enums.py#L15