"Turn right ten degrees" and "turn right ten degrees report new heading" require completely different responses so reporting the heading when not asked for it is neither correct nor required, It may be confusing as the controller will not be expecting it and may talk over it. Indeed, have heard bollockings handed out on busy London and German freqs for just that. After all, you wouldn't think of telling them the heading for "direct XXXXX" unless they ask for it. Would you???
Basic RT discipline, I'd have thought.