Cleanup: EEVEE: Rename aperture to cone angle when it make sense

Aperture for a cone is 2 times the cone angle.

source/blender/draw/engines/eevee/shaders/bsdf_common_lib.glsl

@@ -135,7 +135,7 @@ void accumulate_light(vec3 light, float fac, inout vec4 accum)
   accum += vec4(light, 1.0) * min(fac, (1.0 - accum.a));
 }
 
-/* ----------- Cone Aperture Approximation --------- */
+/* ----------- Cone angle Approximation --------- */
 
 /* Return a fitted cone angle given the input roughness */
 float cone_cosine(float r)

source/blender/draw/engines/eevee/shaders/bsdf_sampling_lib.glsl

@@ -34,7 +34,7 @@ float pdf_hemisphere()
 
 vec3 sample_ggx(vec3 rand, float a2)
 {
-  /* Theta is the aperture angle of the cone */
+  /* Theta is the cone angle. */
   float z = sqrt((1.0 - rand.x) / (1.0 + a2 * rand.x - rand.x)); /* cos theta */
   float r = sqrt(max(0.0, 1.0f - z * z));                        /* sin theta */
   float x = r * rand.y;