Here's an example output from macroexpand:
```
Expr
  head: Symbol thunk
  args: Array{Any}((1,))
    1: Core.CodeInfo
      code: Array{Any}((2,))
        1: Expr
          head: Symbol toplevel
          args: Array{Any}((17,))
            1: Expr
              head: Symbol hygienic-scope
              args: Array{Any}((3,))
                1: LineNumberNode
                2: Module Base.Enums
                3: LineNumberNode
            2: Expr
              head: Symbol hygienic-scope
              args: Array{Any}((3,))
                1: Expr
                2: Module Base.Enums
                3: LineNumberNode
            3: Expr
              head: Symbol hygienic-scope
              args: Array{Any}((3,))
                1: LineNumberNode
                2: Module Base.Enums
                3: LineNumberNode
            4: Expr
              head: Symbol hygienic-scope
              args: Array{Any}((3,))
                1: Expr
                2: Module Base.Enums
                3: LineNumberNode
 ...
```

Currently fails during bootstrap with:
```
LoadError("sysimg.jl", 3, LoadError("Base.jl", 542, ErrorException("cannot document the following expression:\n\n#= mpfr.jl:65 =# @enum MPFRRoundingMode begin\n        #= mpfr.jl:66 =#\n        MPFRRoundNearest\n        #= mpfr.jl:67 =#\n        MPFRRoundToZero\n        #= mpfr.jl:68 =#\n        MPFRRoundUp\n        #= mpfr.jl:69 =#\n        MPFRRoundDown\n        #= mpfr.jl:70 =#\n        MPFRRoundFromZero\n        #= mpfr.jl:71 =#\n        MPFRRoundFaithful\n    end\n\n'@enum' not documentable. See 'Base.@__doc__' docs for details.\n")))
```


Perhaps we can do better than wrapping each `Expr(:toplevel, ...)` arg
individually, or I should be filtering out the LineNumberNodes?

---------

Co-authored-by: Keno Fischer <keno@juliacomputing.com>
Co-authored-by: Keno Fischer <keno@juliahub.com>