"Cel shading or toon shading is a type of non-photorealistic rendering designed to make computer graphics appear to be hand-drawn. Cel-shading is often used to mimic the style of a comic book or cartoon."
Just outlining the pixels isn't exactly cel shading.
If the lines only showed up on the edges of surfaces instead of in the textures, then it could be considered cel-shading, I think.
Also, if the lines were only dark, instead of having dark and light lines.
When you have mipmapping enabled, objects in the background appear to be cel-shaded, but this is only because the mipmapping blurs the textures before the shader is applied.