Put cursor inside the installer window after post-update hook

https://github.com/chrisbra/unicode.vim/issues/16

plug.vim

@@ -793,6 +793,7 @@ function! s:do(pull, force, todo)
       else
         let error = 'Invalid hook type'
       endif
+      call s:switch_in()
       call setline(4, empty(error) ? (getline(4) . 'OK')
                                  \ : ('x' . getline(4)[1:] . error))
       if !empty(error)