Create new undo point for insert_item() and complete_common_string()

Author: Shougo

autoload/ddc/map.vim

@@ -40,6 +40,9 @@ function ddc#map#complete_common_string() abort
     return ''
   endif
 
+  " Create new undo point
+  let &undolevels = &undolevels
+
   let chars = ''
   " NOTE: Change backspace option to work <BS> correctly
   if mode() ==# 'i'
@@ -87,6 +90,9 @@ function ddc#map#insert_item(number) abort
           \ | endif
   endif
 
+  " Create new undo point
+  let &undolevels = &undolevels
+
   let chars = ''
   " NOTE: Change backspace option to work <BS> correctly
   if mode ==# 'i'