Could you add an option to disable the LSP? #25

I've been doing some Arduino projects and haven't been able to get them working with the SourceKit LSP very well, I've had better luck playing around with clangd (although it isn't perfect either). Because Icarus provides the syntax grammars I can't run both extensions at the same time though.

My hack, as aluded to in the readme, was to copy the syntaxes & queries into Clangd and run that extension instead. A better solution might be to have a "none" option to the Toolchain configuration that stops a LanguageClient from being created. Let me know what you think. 😊

Thanks,
Rob