colsizes does not support a mixed vector without trickery

[asinghvi17]

Trying to create a GridLayout like so,

GridLayout(5, 3; colsizes = [Relative(0.1), Relative(0.5), Relative(0.4)])

works fine, but if I try to pass a mixture of size types into colsizes,

GridLayout(1, 3; colsizes = [Fixed(5), Auto(), Fixed(5)])

I get an error:

ERROR: Illegal sizes value Any[Fixed(5.0f0), Auto(true, 1.0f0), Fixed(5.0f0)]

I can fix this by strictly typing the array as a Vector{Makie.GridLayoutBase.ContentSize}, but that seems inefficient and is impossible for users to discover since there's no documentation about it.

Potential solutions to this are:

• Perform explicit vector type unioning in convert_contentsizes(n::Int64, sizes::Vector{Any}) (found at src/gridlayout.jl:332) and check the result of that in order to convert/dispatch.
• Set Fixed, Auto, Relative, etc. to have a supertype AbstractSize or something, which will make at least this syntax pass (passing real numbers will not, that'll probably still need the explicit vector type union)

[jkrumbiegel]

Yeah the vector needs a convert, so the first option.