Message "failed to highlight code" in every step after @enter #303
Description
I get this message when using @enter in a fresh julia environment (Debugger v0.7.0, Julia 1.7.1 on Fedora 35):
julia> using Debugger
julia> @enter sin(1)
failed to highlight code, TypeError(Symbol("keyword argument"), :bold, Union{Nothing, Bool}, :nothing)
failed to highlight code, TypeError(Symbol("keyword argument"), :bold, Union{Nothing, Bool}, :nothing)
In sin(x) at math.jl:1218
1218 @eval function ($f)(x::Real)
>1219 xf = float(x)
1220 x === xf && throw(MethodError($f, (x,)))
1221 return ($f)(xf)
1222 end
About to run: (float)(1)
1|debug>
The message disappeared when I changed all appearances of :nothing to nothing in Format.render at line 201 of printing.jl, but I only had a very superficial look on the code so I'm not sure if that would be the right fix.