feat: 2-arg ustrip for affine units

Author: MilesCranmer

src/affine_dimensions.jl

@@ -114,3 +114,23 @@ function aff_uparse(s::AbstractString)
     ex = AffineUnits.map_to_scope(Meta.parse(s))
     return eval(ex)::AffineUnit{DEFAULT_DIM_BASE_TYPE}
 end
+
+"""
+    ustrip(unit::AffineUnit, q::UnionAbstractQuantity)
+
+Convert a quantity `q` to the numerical value in terms of affine units specified by `unit`,
+then strip the units. This allows getting the numerical value in terms of degrees Celsius or Fahrenheit.
+
+# Examples
+```julia
+julia> ustrip(ua"degC", 27ua"degC")
+27.0
+
+julia> ustrip(ua"degF", 300u"K")
+80.33000000000003
+```
+"""
+function ustrip(unit::AffineUnit, q::UnionAbstractQuantity)
+    unit.basedim == dimension(q) || throw(DimensionError(unit, q))
+    return (ustrip(q) - unit.offset) / unit.scale
+end