docs: translate Spanish comment to English in SimpleExponentialSmoothing notebook (#1129)

Co-authored-by: Saul <saul.caballero.ramirez@gmail.com>

Author: kalichiruvelli-art

nbs/docs/models/SimpleExponentialSmoothing.ipynb

@@ -525,7 +525,7 @@
                 "plot_pacf(df[\"y\"],  lags=30, ax=axs[1],color=\"lime\")\n",
                 "axs[1].set_title('Partial Autocorrelation')\n",
                 "\n",
-                "#plt.savefig(\"Gráfico de Densidad y qq\")\n",
+                "#plt.savefig(\"Density and QQ Plot\")\n",
                 "plt.show();"
             ]
         },