Added amp hour and millijoule (#704)

* Added Millijoule and Ampere hour

* Updated A-h converson constants in ElectricCharge.json to match contribution guide and fixed test stubs

* Added milli, kilo, and mega A-h prefixes

* Updating based on comments from @angularsen on PR #704

* Updating charge units to match library conventions

Author: thebhef

Common/UnitDefinitions/ElectricCharge.json

@@ -19,6 +19,19 @@
           "Abbreviations": [ "C" ]
         }
       ]
+    },
+    {
+      "SingularName": "AmpereHour",
+      "PluralName": "AmpereHours",
+      "FromUnitToBaseFunc": "x/2.77777777777e-4",
+      "FromBaseToUnitFunc": "x*2.77777777777e-4",
+      "Prefixes": [ "Milli", "Kilo", "Mega" ],
+      "Localization": [
+        {
+          "Culture": "en-US",
+          "Abbreviations": [ "A-h", "Ah" ]
+        }
+      ]
     }
   ]
 }

Common/UnitDefinitions/Energy.json

@@ -18,7 +18,7 @@
       },
       "FromUnitToBaseFunc": "x",
       "FromBaseToUnitFunc": "x",
-      "Prefixes": [ "Kilo", "Mega" ],
+      "Prefixes": [ "Milli", "Kilo", "Mega" ],
       "Localization": [
         {
           "Culture": "en-US",

UnitsNet.Tests/CustomCode/ElectricChargeTests.cs

@@ -28,5 +28,9 @@ namespace UnitsNet.Tests.CustomCode
     public class ElectricChargeTests : ElectricChargeTestsBase
     {
         protected override double CoulombsInOneCoulomb => 1;
+        protected override double MilliampereHoursInOneCoulomb => 2.77777777777e-1;
+        protected override double AmpereHoursInOneCoulomb => 2.77777777777e-4;
+        protected override double KiloampereHoursInOneCoulomb => 2.77777777777e-7;
+        protected override double MegaampereHoursInOneCoulomb => 2.77777777777e-10;
     }
 }

UnitsNet.Tests/CustomCode/EnergyTests.cs

@@ -34,6 +34,8 @@ public class EnergyTests : EnergyTestsBase
 
         protected override double ErgsInOneJoule => 10000000;
 
+        protected override double MillijoulesInOneJoule => 1000;
+
         protected override double TerawattHoursInOneJoule => 2.77777778e-16;
 
         protected override double ThermsEcInOneJoule => 9.4781712031331720001278504447561e-9;