fixed doctests on 1.3

Author: torfjelde

src/compiler.jl

@@ -140,7 +140,7 @@ variables.
 
 # Example
 ```jldoctest; setup=:(using Distributions)
-julia> _, _, vns = DynamicPPL.unwrap_right_left_vns(MvNormal(1, 1.0), randn(1, 2), @varname(x)); string(vns[end])
+julia> _, _, vns = DynamicPPL.unwrap_right_left_vns(MvNormal([1.0, 1.0], [1.0 0.0; 0.0 1.0]), randn(2, 2), @varname(x)); string(vns[end])
 "x[:,2]"
 
 julia> _, _, vns = DynamicPPL.unwrap_right_left_vns(Normal(), randn(1, 2), @varname(x[:])); string(vns[end])