Neovim Lsp usage without plugins

-- set up the language servers
vim.lsp.config('gopls', {
    filetypes = { 'go' },
    cmd = { 'gopls' },
    root_markers = { 'go.mod', 'go.work' }
})
vim.lsp.enable('gopls')

vim.lsp.config('zls', {
    filetypes = { 'zig' },
    cmd = { 'zls' },
})
vim.lsp.enable('zls')

vim.api.nvim_create_autocmd('LspAttach', {
    desc = 'Configure Lsp',
    callback = function(event)
        local id = vim.tbl_get(event, 'data', 'client_id')
        local client = id and vim.lsp.get_client_by_id(id)
        if client == nil then
            return
        end
        if client.supports_method('textDocument/inlayHint') then
            vim.lsp.inlay_hint.enable(true, {bufnr = event.buf})
        end
        if client.supports_method('textDocument/completion') then
            vim.lsp.completion.enable(true, client.id, bufnr, { autotrigger = true })
        end
    end,
})

-- Neovim keybindings by default:
-- <C-w>d: floating diagnostics window
-- [d, ]d: prev and next diagnostics
-- K: show docs for symbol under cursor
-- grn: renames references
-- gra: show LSP actions
-- grr: show references
-- gri: show implementations
-- gO: lists symbols in buffer
-- <C-s>: shows signature
-- <C-]>: jump to definition