Split abbreviations into a separate plugin

[vunhatchuong]

Hi, I don't use lean.nvim, but I find the abbreviations feature really useful.

Would you be interested in splitting it into a separate plugin so others can also take advantage of it?

[Julian]

Hey there! It's been requested before, I'm definitely open to it though it hasn't been high on the priority list to do. But I can try to find a bit of time to do so.