vk: rt: fixup

ref/vk/TODO.md

@@ -1,4 +1,5 @@
 ## Next
+- [ ] white furnace test
 - [ ] performance profiling and comparison
 
 ## 2024-01-23 E368

ref/vk/shaders/denoiser.comp

@@ -387,7 +387,7 @@ void main() {
 	colour = LINEARtoSRGB(colour);
 
 // See issue https://github.com/w23/xash3d-fwgs/issues/668, map test_blendmode_additive_alpha.
-// Adding emissive_blend to the final color in the *incorrect* sRGB-¿ space. It makes
+// Adding emissive_blend to the final color in the *incorrect* sRGB-γ space. It makes
 // it look much more like the original. Adding emissive in the *correct* linear space differs
 // from the original a lot, and looks perceptively worse.
 	colour += legacy_blend.rgb;