fix(nvim-plug): make sure buf modifiable is true

Author: wsdjeg

bundle/nvim-plug/lua/plug/ui.lua

@@ -98,6 +98,7 @@ M.open = function()
     })
   end
   if vim.api.nvim_buf_is_valid(bufnr) then
+    vim.api.nvim_set_option_value('modifiable', true, { buf = bufnr})
     vim.api.nvim_buf_set_lines(bufnr, 0, -1, false, build_context())
     vim.api.nvim_set_option_value('modifiable', false, { buf = bufnr})
   end