Add compatibility for simultaneous coc.nvim and sorbet (or other LSPs)

The [instructions for using coc.nvim](https://github.com/dense-analysis/ale#faq-coc-nvim) say to disable LSP support - but this also disables other Linters.

I spent an hour frustrated at ale because sorbet wasn't running - I could see that sorbet was ignored in ALEInfo but had no idea why. I even dug into the source code and couldn't grok what was going on. As an end user, I don't know that sorbet is an LSP while others are not. Now I understand that this is because `sorbet` runs as an LSP, and that makes it incompatible with using coc as instructed.

Is there any way to use an LSP like sorbet while also using coc properly? At minimum, perhaps it would be good to add a note to the coc instructions that they will disable LSP linters, with a list of which those are?