Feat(nvim): add option for buffer completion

nvim/.config/nvim/lua/plugins/completion.lua

@@ -24,6 +24,16 @@ return  {
             sources = cmp.config.sources({
                 { name = 'nvim_lsp' },
                 { name = 'vsnip' }, -- For vsnip users.
+                { name = 'path' },
+                { 
+                    name = 'buffer',
+                    option = {
+                        keyword_length = 3,
+                        get_bufnrs = function()
+                            return vim.api.nvim_list_bufs()
+                        end
+                    }
+                },
             }, {
                     { name = 'buffer' },
                 })