Feature request: Tell Vim and Emacs to use diff filetype for re files

[rmloveland]

E.g., at the end of the file, prefaced by whatever is the re file's comment character (#?):

Local Variables:
mode: diff
End:

vim: set ft=diff:

Perhaps down the road a new filetype will need to be implemented ("re-mode" ?) that properly highlights the comments in addition to the diffs, but for now I've been using diff-mode.