No message when try to use LSP with no project root.

[j0ng4b]

This given me many headacher when I was using clangd without a project root, simple standalone test file, and noticed that clangd doens't even get executed. Then I found this when trying to find the issue on source code:

ale/autoload/ale/lsp_linter.vim

Lines 430 to 434 in 607f33a

	if empty(l:root) && a:linter.lsp isnot# 'tsserver'
	" If there's no project root, then we can't check files with LSP,
	" unless we are using tsserver, which doesn't use project roots.
	return 0
	endif

So, if showed some message to user (like me) would be really appreciated, because if I knew this before I wouldn't spent much time to find this "issue".

Please show some warning about this limitation or make possible run lsp without project root like other lsp clients.

[w0rp]

I agree. I would like to reveal it probably in :ALEInfo. Just something that doesn't nag people.