Inconsistent `NLPModelsMeta.islp`

[klamike]

I noticed QuadraticModels assigns islp based on ncon, which seems strange.

QuadraticModels.jl/src/qpmodel.jl

Line 140 in 90fdaaa

islp = (ncon == 0);

In presolve, it seems to (correctly?) use nnzh

QuadraticModels.jl/src/presolve/presolve.jl

Line 377 in 90fdaaa

islp = (nnzh == 0);

[tmigot]

Oh... that looks like a bug. Do you want to open a pull request to fix this?