Improve docs

Author: MilesCranmer

docs/src/types.md

@@ -40,6 +40,19 @@ which is subtyped to `Any`.
 ```@docs
 GenericQuantity
 AbstractGenericQuantity
+```
+
+In the other direction, there is also `RealQuantity`,
+which is subtyped to `Real`.
+
+```@docs
+RealQuantity
+AbstractRealQuantity
+```
+
+More general, these are each contained in the following:
+
+```@docs
 UnionAbstractQuantity
 DynamicQuantities.ABSTRACT_QUANTITY_TYPES
 ```

test/unittests.jl

@@ -1,5 +1,5 @@
 using DynamicQuantities
-using DynamicQuantities: FixedRational, NoDims
+using DynamicQuantities: FixedRational, NoDims, AbstractSymbolicDimensions
 using DynamicQuantities: DEFAULT_QUANTITY_TYPE, DEFAULT_DIM_BASE_TYPE, DEFAULT_DIM_TYPE, DEFAULT_VALUE_TYPE
 using DynamicQuantities: array_type, value_type, dim_type, quantity_type
 using DynamicQuantities: GenericQuantity, with_type_parameters, constructorof