doc: mention the debug log dictionary in the docstrings

Author: franckgaga

src/controller/execute.jl

@@ -491,7 +491,8 @@ If supported by `mpc.optim`, it warm-starts the solver at:
 where ``\mathbf{Δu}_{k-1}(k+j)`` is the input increment for time ``k+j`` computed at the 
 last control period ``k-1``. It then calls `JuMP.optimize!(mpc.optim)` and extract the
 solution. A failed optimization prints an `@error` log in the REPL and returns the 
-warm-start value.
+warm-start value. A failed optimization also prints [`getinfo`](@ref) results in
+the debug log [if activated](https://docs.julialang.org/en/v1/stdlib/Logging/#Example:-Enable-debug-level-messages).
 """
 function optim_objective!(mpc::PredictiveController{NT}) where {NT<:Real}
     model, optim = mpc.estim.model, mpc.optim

src/estimator/mhe/execute.jl

@@ -369,7 +369,8 @@ If supported by `estim.optim`, it warm-starts the solver at:
 where ``\mathbf{ŵ}_{k-1}(k-j)`` is the input increment for time ``k-j`` computed at the 
 last time step ``k-1``. It then calls `JuMP.optimize!(estim.optim)` and extract the
 solution. A failed optimization prints an `@error` log in the REPL and returns the 
-warm-start value.
+warm-start value. A failed optimization also prints [`getinfo`](@ref) results in
+the debug log [if activated](https://docs.julialang.org/en/v1/stdlib/Logging/#Example:-Enable-debug-level-messages).
 """
 function optim_objective!(estim::MovingHorizonEstimator{NT}) where NT<:Real
     model, optim = estim.model, estim.optim