Use diagnostics open_float instead of virtual_lines in neovim

I didn’t like virtual_lines for diagnostics since it pushes the text down, so I decided to use a floating window instead.

Here’s an example, it will show the floating diagnostics window on CursorHold and InsertLeave.

Also disable diagnostics while in Insert mode.

local group = vim.api.nvim_create_augroup('OoO', {})

local function au(typ, pattern, cmdOrFn)
	if type(cmdOrFn) == 'function' then
		vim.api.nvim_create_autocmd(typ, { pattern = pattern, callback = cmdOrFn, group = group })
	else
		vim.api.nvim_create_autocmd(typ, { pattern = pattern, command = cmdOrFn, group = group })
	end
end

au({ 'CursorHold', 'InsertLeave' }, nil, function()
	local opts = {
		focusable = false,
		scope = 'cursor',
		close_events = { 'BufLeave', 'CursorMoved', 'InsertEnter' },
	}
	vim.diagnostic.open_float(nil, opts)
end)

au('InsertEnter', nil, function()
	vim.diagnostic.enable(false)
end)

au('InsertLeave', nil, function()
	vim.diagnostic.enable(true)
end)