feat(lsp): migrate from blink.cmp to built-in completion

after/lsp/gopls.lua

@@ -1,4 +1,3 @@
-local lsp = require("lsp")
 local util = require("util")
 
 ---@type vim.lsp.Config
@@ -13,8 +12,6 @@ return {
         },
     },
     on_attach = function(client, bufnr)
-        lsp.on_attach(client, bufnr)
-
         vim.keymap.set("n", "<leader>lf", function()
             util.format({
                 buf = bufnr,