`02 Combined Image Sampler` slang shader code typo

[JustinBraben]

In the 06 Texture Mapping/02 Combined image sampler chapter it states to try manipulating the fragment shader like so:

[shader("fragment")]
float4 fragMain(VSOutput vertIn) : SV_TARGET {
   return vec4(vertIn.fragColor * texture.Sample(vertIn.fragTexCoord).rgb, 1.0);
}

But I believe it should return float4(

[shader("fragment")]
float4 fragMain(VSOutput vertIn) : SV_TARGET {
   return float4(vertIn.fragColor * texture.Sample(vertIn.fragTexCoord).rgb, 1.0);
}

I can make a PR for it if you wish.

[SaschaWillems]

That's def wrong. vec4 is GLSL. Feel free to to do a PR.