gencppbindings fails with: "Error: only single underscores may occur in a token and token may not end with an underscore"

[DevKevinYG]

This issue can be reproduced by naming variables in cpp like this:

UENUM(BlueprintType)
enum class ENumTest: uint8
{
    _1_ = 1, //causes error as it ends with underscore
    _2_ = 2,
    _3_ = 3,
    _4_ = 4,
     //and so on
};

UFUNCTION(BlueprintCallable)
static void Func(const int32 a__b);