proposal: vim syntax for lfrc

[nnzv]

Why?

End-users could easily differentiate stuff:

# Is this a comment?
set shellopts '-eu'

# This is a comment!
set shellopts '-eu'

[kmarius]

There is https://github.com/camnw/lf-vim. It could use some updates such as missing config options that were added in the past year.