Add [oD ]oD coD mappings for 'windo diff'

[ericbn]

as the lower case [cod, etc. do only 'diffthis' or 'diffoff' in the current window, and this then needs to be repeated for at least the second window to be compared. A usual workspace with two split windows to be compared would only need a 'windo diffthis'...

[ericbn]

I see your comment:

And I really hate going down the windo rabbit hole.

Isn't diffthis an exception here, as it might pair well with windo in it's usual usage?

[ericbn]

Closing this as it can be solved with a custom mapping like

nnoremap <leader>d :windo <C-R>=&diff ? 'diffoff' : 'diffthis'<CR><CR>