show only file marks from Marks

[ccshao]

• [x] I have fzf 0.30.0 or above
• [x] I have read through https://github.com/junegunn/fzf.vim/blob/master/README.md
• [x] I have read through https://github.com/junegunn/fzf/blob/master/README-VIM.md
• [x] I have read through the manual page of fzf (man fzf)
• [x] I have searched through the existing issues

Marks shows both file marks and buffer marks, how to config it to only output the file marks, or select file marks from the output? Many thanks!

[ufst-mathias]

+1