inserted text disappear when snippetSupport is enabled

[Warashi]

1. install gopls

2. use vimrc below

   let s:cache_dir = expand("~/.cache/nvim/dein")
   let s:pum = s:cache_dir . "/repos/github.com/Shougo/pum.vim"
   let s:denops = s:cache_dir . "/repos/github.com/vim-denops/denops.vim"
   let s:ddc = s:cache_dir . "/repos/github.com/Shougo/ddc.vim"
   let s:ddc_source_nvim_lsp = s:cache_dir . "/repos/github.com/Shougo/ddc-source-nvim-lsp"
   let s:ddc_ui_pum = s:cache_dir . "/repos/github.com/Shougo/ddc-ui-pum"
   
   let s:lspconfig = s:cache_dir . "/repos/github.com/neovim/nvim-lspconfig"
   
   execute 'set runtimepath+=' . s:pum
   execute 'set runtimepath+=' . s:denops
   execute 'set runtimepath+=' . s:ddc
   execute 'set runtimepath+=' . s:ddc_source_nvim_lsp
   execute 'set runtimepath+=' . s:ddc_ui_pum
   execute 'set runtimepath+=' . s:lspconfig
   
   inoremap <silent><expr> <C-n> pum#visible() ? pum#map#select_relative(+1) : ddc#map#manual_complete()
   inoremap <silent><expr> <C-y> pum#map#confirm()
   
   call ddc#custom#patch_global(#{ ui: "pum", sources: ["nvim-lsp"], autoCompleteEvents: []})
   call ddc#enable()
   
   lua << EOF
   local capabilities = vim.lsp.protocol.make_client_capabilities()
   capabilities.textDocument.completion.completionItem.snippetSupport = true
   require("lspconfig").gopls.setup({ capabilities = capabilities })
   EOF

3. make temporary directory
4. do go mod init exmaple.com/ddc-source-nvim-lsp-test/main
5. open main.go with nvim
6. type as below

   package main

7. enter newline with Insert mode, then type func<C-n><C-n><C-y> slowly slowly because make first <C-n> successfully open completion menu.

[Warashi]

I forgot to set snippetEngine documented below. https://github.com/Shougo/ddc-source-nvim-lsp/blob/738b86b5c16ee8f396d9437e6aea17780e325ef1/doc/ddc-source-nvim-lsp.txt#L67-L74

The problem is solved after configure these settings. I'm sorry, there is no problem without my settings.

[Shougo]

I have checked the code and it is the problem of ddc-source-nvim-lsp. Please update.