Go easy on the gamut expansion.

Trying to fix reported cases of extreme color saturation. Gamut expansion range is now from 0.0 to 0.1, for the default saturation it is set to 0.05.

Resources/Shaders/oolite-final-hdr.fragment

@@ -744,7 +744,7 @@ void main()
 	vec3 result = ACESFilmRec2020OrReinhardHDR(mix(hdrColor, luma, clamp(t * 80 / uMaxBrightness, 0.0, 1.0)) * uPaperWhiteBrightness * 0.0125);
 
 	// gamut expansion here
-	result = expandGamut(result, 1.0f / pow(2.0f, uSaturation));
+	result = expandGamut(result, uSaturation * 0.05f);
 
 #if HDR_HEATMAP
 	{