There is no longer the need to apply a diff, instead rely on
replace-buffer-contents which does the diffing internally,
avoiding the need to call an external diff command.
This should also support MS-Windows which may not have diff installed.
Remove the need for a temporary file, instead handle formatting
in memory using pipes.
replace-buffer-contentswhich does the diffing internally, avoiding the need to call an external diff command. This should also support MS-Windows which may not have diff installed.