minor doc correction

Author: franckgaga

docs/src/manual/nonlinmpc.md

@@ -30,7 +30,7 @@ pendulum. Here, the explicit Euler method discretizes the system to construct a
 ```@example 1
 using ModelPredictiveControl
 function pendulum(par, x, u)
-    g, L, K, m = par        # [m/s], [m], [kg/s], [kg]
+    g, L, K, m = par        # [m/s²], [m], [kg/s], [kg]
     θ, ω = x[1], x[2]       # [rad], [rad/s]
     τ  = u[1]               # [N m]
     dθ = ω

src/state_estim.jl

@@ -203,7 +203,7 @@ Get default integrator quantity per measured outputs `nint_ym` for [`LinModel`](
 
 The measured output ``\mathbf{y^m}`` indices are specified by `i_ym` argument. By default, 
 one integrator is added on each measured outputs. If ``\mathbf{Â, Ĉ}`` matrices of the 
-augmented model becomes unobservable, the integrator is removed. This approach works well 
+augmented model become unobservable, the integrator is removed. This approach works well 
 for stable, integrating and unstable `model` (see Examples).
 
 # Examples