bug#3540: reserve a key + inform other gnu package maintainers and mode-authors

[Arne Babenhauserheide]

I’d love to see an officially reserved key, too (which emacs promises to
keep reserved), ideally a standard letter (which is also readily
available on international keyboards). Any special character (like \)
will prove problematic with international keyboards — and even more with
alternate keyboard layouts.

Naturally the problem with this is that no C-<key> combination is free anymore…

I think I’ll use C-o, because adding newlines behind the point generally
only confuses me when I hit C-o by error, but I assume many people use
it and would be angry to lose the command if it would be made the
default reserved key… 

Another problem with C-o is that C-M-o runs split-current line which
many people might use. 

So selecting a reserved key might take some though - and ideally an
emacs user-survey. 

Best wishes, 
Arne