display modified buffer info column for ddu.vim
display icon for file related to modified buffer
in the image bellow, the modified icon is "●".
![スクリーンショット 2024-01-27 14 04 41](https://private-user-images.githubusercontent.com/50443168/300155854-ee09efd3-ce00-4a5d-81fe-9f8a1150c679.png?jwt=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.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.D3_HSPPED1xUL2Surcd4BCwzYMGoyCsrqZUWdtuDLjI)
https://github.com/vim-denops/denops.vim
https://github.com/Shougo/ddu.vim
call ddu#custom#patch_global(#{
\ columns: ['filename', 'file_buf_modified'],
\ })