make example bench more proper

Author: 1-Bart-1

examples/bench.jl

@@ -1,6 +1,7 @@
 using LinearAlgebra
 using ControlPlots
 using VortexStepMethod
+using BenchmarkTools
 
 plot = true
 
@@ -38,8 +39,8 @@ llt_solver = Solver(aerodynamic_model_type=:LLT)
 vsm_solver = Solver(aerodynamic_model_type=:VSM)
 
 # Step 5: Solve using both methods
-results_vsm = solve(vsm_solver, wa)
-@time results_vsm = solve(vsm_solver, wa)
+@btime results_llt = solve($vsm_solver, $wa)
+@btime results_vsm = solve($vsm_solver, $wa)
 # time Python: 32.0 ms Ryzen 7950x
 # time Julia:   0.6 ms Ryzen 7950x
 #               0.8 ms laptop, performance mode, battery