Update constructor documentation

Author: adamgraham

Runtime/EqualityComparers/DoubleEqualityComparer.cs

@@ -14,7 +14,8 @@ public sealed class DoubleEqualityComparer : IEqualityComparer<double>
         public int digits;
 
         /// <summary>
-        /// Creates a new DoubleEqualityComparer.
+        /// Creates a new DoubleEqualityComparer with a default of 3 decimal
+        /// digits to compare when determining equality.
         /// </summary>
         public DoubleEqualityComparer()
         {

Runtime/EqualityComparers/FloatEqualityComparer.cs

@@ -14,7 +14,8 @@ public sealed class FloatEqualityComparer : IEqualityComparer<float>
         public int digits;
 
         /// <summary>
-        /// Creates a new FloatEqualityComparer.
+        /// Creates a new FloatEqualityComparer with a default of 3 decimal
+        /// digits to compare when determining equality.
         /// </summary>
         public FloatEqualityComparer()
         {