Possible to run a custom command with a pipe without subprocess: yes?

[bdach]

I have the following custom command definition:

customCommands:
  - key: y
    context: files
    command: "echo \"\\`\\`\\`diff\n`git diff`\n\\`\\`\\`\" | xclip -sel clipboard"
    description: yank pending changes as markdown diff code block
    subprocess: yes

The use case is to take all of the pending changes in the current index and put them into the X clipboard for pasting elsewhere (like github review comments). As it stands, the command takes two keypresses to complete: the initial Y, and then a Return because of subprocess: yes. I would like to get rid of the subprocess, but not doing so causes the command to seemingly spin endlessly, even though the code block is available in the system clipboard:

I suspect this is because of the pipe redirection. Is there an easy lazygit-config-only way I can make this work in only the one Y keypress?