I am making my .vimrc. Basically I want my omnifunc menu to popup on any keypress while in insert mode. The basic idea is to
cnoremap <C-x><C-o> <any key>
At some point I will probably limit it to the alphabet if I can. And then I will probably limit it to be the second or third letter of a word. So, how can I remap all (alphabetic)keys to C-x C-o?