fix: replaced deprecated vim.diagnostic.disable()

[EliTyson]

Replace Deprecated vim.diagnostic.disable()

vim.diagnostic.disable() was deprecated in Neovim 0.10
https://neovim.io/doc/user/deprecated/#vim.diagnostic.disable()

This causes an error when using the "Snippet List" feature: require("luasnip.extras.snippet_list").open().

Replacing vim.diagnostic.disable() with vim.diagnostic.enable(false) resolves the problem.

[EliTyson]

Is a version checking necessary here?

if vim.fn.has("nvim-0.10") == 1 then
	vim.diagnostic.enable(false, { bufnr = buf })
else
	vim.diagnostic.disable(buf)
end