[cs] refactor duplication of @:noCompletion metadata generation
[cs] refactor duplication of @:noCompletion metadata generation

pleclech/hacking-haxe,pleclech/hacking-haxe,pleclech/hacking-haxe,pleclech/hacking-haxe,pleclech/hacking-haxe,pleclech/hacking-haxe