Fix assertion in GraphMeterMode_makeDetailsMask

Meter.c

@@ -509,7 +509,7 @@ static uint16_t GraphMeterMode_makeDetailsMask(const GraphColorComputeState* pre
 
    // If "rem" is not zero, it should have a minimum value so that
    // (1.0 - rem) will not round to 1.0.
-   assert(rem <= 0.0 || rem >= (1.0 / UINT8_MAX));
+   assert(rem <= 0.0 || rem >= DBL_EPSILON);
 
    double maxBlanks = (1.0 - rem) * 8.0;