Update docstring to README

Author: MilesCranmer

README.md

@@ -24,8 +24,8 @@ For example,
 | `Dual{Complex{Float32}}` | `Float32` |
 
 The standard behavior is to return the *first* type parameter,
-or, if that type has parameters of its own, to recursively
-take the first type parameter until a non-parameterized type is found.
+or, if that type has parameters of its own (such as `Dual{Complex{Float32}}`),
+to recursively take the first type parameter until a non-parameterized type is found.
 
 Packages should write a custom method for `base_numeric_type`
 if this behavior is incompatible with their type.

src/BaseType.jl

@@ -12,13 +12,19 @@ as a measurement or a quantity.
 For example,
 
 | Input Type | Output Type |
-|---|---|
+|:-:|---|
 | `Float32` | `Float32` |
 | `ComplexF32` | `Float32` |
 | `Measurement{Float32}` | `Float32` |
-| `Rational{Int8}` | `Int8` |
 | `Dual{BigFloat}` | `BigFloat` |
-| `Quantity{Float32,Dimensions}` | `Float32` |
+| `Rational{Int8}` | `Int8` |
+| `Quantity{Float32, ...}` | `Float32` |
+| `Quantity{Measurement{Float32}, ...}` | `Float32` |
+| `Dual{Complex{Float32}}` | `Float32` |
+
+The standard behavior is to return the *first* type parameter,
+or, if that type has parameters of its own (such as `Dual{Complex{Float32}}`),
+to recursively take the first type parameter until a non-parameterized type is found.
 """
 @generated function base_numeric_type(::Type{T}) where {T}
     # This uses a generated function for type stability in Julia <=1.9,