Allow languages to support multiple suffixes

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