Add option to not append left parenthesis after function name

[blahgeek]

All other language servers I've used, as well as other C/C++ completion servers like ycm, do not append left parenthesis after function name. I'd like to see an option to disable this feature.

[jacobdufault]

I suspect this is from snippets. There should be an option in config.h to disable but I don't see it at the moment (it may have been removed).