Add Energy divided by Power equals TimeSpan operator (#1113)

Author: dglozano

UnitsNet.Tests/CustomCode/EnergyTests.cs

@@ -121,6 +121,13 @@ public void EnergyDividedByDurationEqualsPower()
             Assert.Equal(4, p.Watts);
         }
 
+        [Fact]
+        public void EnergyDividedByPowerEqualsDuration()
+        {
+            Duration d = Energy.FromKilowattHours(100) / Power.FromKilowatts(20);
+            Assert.Equal(5, d.Hours);
+        }
+
         [Fact]
         public void EnergyTimesFrequencyEqualsPower()
         {

UnitsNet/CustomCode/Quantities/Energy.extra.cs

@@ -19,6 +19,12 @@ public partial struct Energy
             return Power.FromWatts(energy.Joules / duration.Seconds);
         }
 
+        /// <summary>Get <see cref="Duration"/> from <see cref="Energy"/> divided by <see cref="Power"/>.</summary>
+        public static Duration operator /(Energy energy, Power power)
+        {
+            return Duration.FromSeconds(energy.Joules / power.Watts);
+        }
+
         /// <summary>Get <see cref="Power"/> from <see cref="Energy"/> times <see cref="Frequency"/>.</summary>
         public static Power operator *(Energy energy, Frequency frequency)
         {
@@ -42,13 +48,13 @@ public partial struct Energy
         {
             return TemperatureDelta.FromKelvins(energy.Joules / entropy.JoulesPerKelvin);
         }
-        
+
         /// <summary>Get <see cref="SpecificEnergy"/> from <see cref="Energy"/> divided by <see cref="Mass"/> </summary>
         public static SpecificEnergy operator /(Energy energy, Mass mass)
         {
             return SpecificEnergy.FromJoulesPerKilogram(energy.Joules / mass.Kilograms);
         }
-        
+
         /// <summary>Get <see cref="Mass"/> from <see cref="Energy"/> divided by <see cref="SpecificEnergy"/>.</summary>
         public static Mass operator /(Energy energy, SpecificEnergy specificEnergy)
         {