Update ILU to IncompleteLU in preconditioning docs

Author: fredrikekre

docs/src/preconditioning.md

@@ -17,7 +17,7 @@ Pl = Pr = IterativeSolvers.Identity()
 ## Available preconditioners
 IterativeSolvers.jl itself does not provide any other preconditioners besides `Identity()`, but recommends the following external packages:
 
-- [ILU.jl](https://github.com/haampie/ILU.jl) for incomplete LU decompositions (using drop tolerance);
+- [IncompleteLU.jl](https://github.com/haampie/IncompleteLU.jl) for incomplete LU decompositions (using drop tolerance).
 - [IncompleteSelectedInversion.jl](https://github.com/ettersi/IncompleteSelectedInversion.jl) for incomplete LDLt decompositions.
 - [AlgebraicMultigrid.jl](https://github.com/JuliaLinearAlgebra/AlgebraicMultigrid.jl) for some algebraic multigrid (AMG) preconditioners.
 - [Preconditioners.jl](https://github.com/mohamed82008/Preconditioners.jl) which wraps a bunch of preconditioners from other packages. If you are a beginner or want to try different ones quickly, this is good starting place.