You can use "pop" as a verb to mean "stand out" or "be prominent." This is now common in situations like fashion, graphic design, decorating a house, etc. Examples: The red scarf really pops against the gray suit. Make the title a bright color so it pops. From there, people started using it as a noun with the same general meaning. Example: When I wear a gray suit, I add a red scarf for a pop of color. "A pop of color" is the most common use, I think. People also say a pop of red, a pop of blue, a pop of white, etc. I haven't heard "a pop of shine" but it makes sense.

A pop of = a little bit of, a flash of. Imagine a bubble that stays, pops, and then goes but leaves something behind.