How to add edge color to histogram?

I wanna make edges of histogram visible. Default histogram dont let us to see clearly. Im talking about this one:

As you can see there is no clear border lines. So I wanna make it like this:
Ekran Alıntısı

I think I explained my problem clearly. It seems like an easy thing, but I dont know why but I couldn’t find how can I do.

Can you help me,
Thanks in advance!!