refactor: remove generate_factorized_W

Author: AayushSabharwal

src/systems/abstractsystem.jl

@@ -113,17 +113,6 @@ the arguments to the internal [`build_function`](@ref) call.
 """
 function generate_jacobian end
 
-"""
-```julia
-generate_factorized_W(sys::AbstractSystem, dvs = unknowns(sys), ps = parameters(sys),
-                      expression = Val{true}; sparse = false, kwargs...)
-```
-
-Generates a function for the factorized W matrix of a system. Extra arguments control
-the arguments to the internal [`build_function`](@ref) call.
-"""
-function generate_factorized_W end
-
 """
 ```julia
 generate_hessian(sys::AbstractSystem, dvs = unknowns(sys), ps = parameters(sys),