Add `lin_nnzj` and `nln_nnzj` in show

[tmigot]

This is the function that needs to be modified:

NLPModels.jl/src/nlp/show.jl

Line 71 in 3b5ec8e

function lines_of_description(m::AbstractNLPModelMeta)

[tmigot]

They are also missing from the readme