Fix light overflow of u8 if light is saturated at 255 (#10305)

src/light.cpp

@@ -18,6 +18,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 */
 
 #include "light.h"
+#include <algorithm>
 #include <cmath>
 #include "util/numeric.h"
 #include "settings.h"
@@ -81,9 +82,11 @@ void set_light_table(float gamma)
 		// Strictly speaking, rangelim is not necessary here—if the implementation
 		// is conforming. But we don’t want problems in any case.
 		light_LUT[i] = rangelim((s32)(255.0f * brightness), 0, 255);
+
 		// Ensure light brightens with each level
-		if (i > 1 && light_LUT[i] <= light_LUT[i - 1])
-			light_LUT[i] = light_LUT[i - 1] + 1;
+		if (i > 0 && light_LUT[i] <= light_LUT[i - 1]) {
+			light_LUT[i] = std::min((u8)254, light_LUT[i - 1]) + 1;
+		}
 	}
 }