SL-17702: PBR: Document lights are in linear from C++ side

indra/newview/app_settings/shaders/class3/deferred/multiPointLightF.glsl

@@ -100,7 +100,7 @@ void main()
 
         for (int light_idx = 0; light_idx < LIGHT_COUNT; ++light_idx)
         {
-            vec3  lightColor = light_col[ light_idx ].rgb;
+            vec3  lightColor = light_col[ light_idx ].rgb; // Already in linear, see pipeline.cpp: volume->getLightLinearColor();
             float falloff    = light_col[ light_idx ].a;
             float lightSize  = light    [ light_idx ].w;
             vec3  lv         =(light    [ light_idx ].xyz - pos);

indra/newview/app_settings/shaders/class3/deferred/pointLightF.glsl

@@ -106,7 +106,7 @@ void main()
         vec3 colorEmissive = spec.rgb; // PBR sRGB Emissive.  See: pbropaqueF.glsl
         vec3 packedORM     = texture2DRect(emissiveRect, tc).rgb; // PBR linear packed Occlusion, Roughness, Metal. See: pbropaqueF.glsl
         float lightSize    = size;
-        vec3 lightColor    = color;
+        vec3 lightColor    = color; // Already in linear, see pipeline.cpp: volume->getLightLinearColor();
 
         vec3 c_diff, reflect0, reflect90;
         float alphaRough, specWeight;