shellStartup notification should describe the changes to be made

I had this pop up when I opened a window

This is a pretty loud notification, and I have my dotfiles set up exactly how I want them. If I wasn't partial to VS Code and filing this bug I would definitely have hit "No" :)

Also, even after allowing it, it never told me what changes were made, and just pushed this notification

I would expect the dialog to have a "view changes" button that opens a diff editor and then lets me accept or deny the changes at that point (can use the editor content button and re-open the dialog if they close the file without actioning on it) or at least a link to some documentation