allow disabling fontification for function/method calls
allow disabling fontification for function/method calls

Fontifying function and method calls is unusual for emacs modes.
Personally I think it improves readability, others disagree, so it's
customizable now.

Closes gh-17

ibukanov/go-mode.el,dominikh/go-mode.el,magastzheng/go-mode.el,emacsmirror/go-mode,kimiby/go-mode.el,gorakhargosh/go-mode.el,artemave/go-mode.el,tjyang/go-mode.el,codemac/go-mode.el