diff-mode and whitespace-mode

[Dan Nicolaescu]

`diff-show-trailing-whitespaces' sets `whitespace-style' and
`whitespace-trailing-regexp' and then calls `whitespace-mode'.

`diff-mode' could set those 2 variables, and then calling
`whitespace-mode' would show trailing whitespaces in diff-mode, and the
`diff-show-trailing-whitespaces' function could be removed.

The above would work if whitespace-style and whitespace-trailing-regexp
were not used for some other purpose in conjunction with diff-mode.
Stefan asks if that is indeed the case.