Fix issue with unit on macOC (exponents in a string had been displayed as Unicode superscripts)

Author: MartinOtter

docs/src/index.md

@@ -24,10 +24,14 @@ julia> ]add ModiaPlot_PyPlot        # if plotting with PyPlot desired
         add ModiaPlot_CairoMakie    # if plotting with CairoMakie desired
 ```
 
-Note, Modia exports all exported symbols of 
+Note, Modia reexports the following definitions 
 
-- [DifferentialEquations](https://github.com/SciML/DifferentialEquations.jl) and of 
-- [Unitful](https://github.com/PainterQubits/Unitful.jl)
+- `using Unitful`
+- `using DifferentialEquations`
+- and exports functions `CVODE_BDF` and `IDA` of [Sundials.jl](https://github.com/SciML/Sundials.jl).
+
+As a result, it is usually sufficient to have `using Modia` in a model to utilize the relevant 
+functionalities of these packages.
 
 
 ## Release Notes

src/ModiaLang.jl

@@ -550,7 +550,10 @@ function stateSelectionAndCodeGeneration(modStructure, Gexplicit, name, modelMod
             @assert all([un[i] == un[1] for i in 2:length(un)]) "The unit of all elements of state vector must be equal: $var::$(value)"
             un = un[1]
         end
-        return replace(string(un), " " => "*") # Fix since Unitful removes * in unit strings
+        # Transform unit to string representation that is parseable again (see also https://github.com/PainterQubits/Unitful.jl/issues/412):
+        # - Display exponents on units not as superscripts (= default on macOS)
+        # - Replace " " by "*", since Unitful removes "*" when converting to string
+        return replace(repr(un,context = Pair(:fancy_exponent,false)), " " => "*")
     end
 
     function var_startInitFixed(v_original)