backwards_ecal: update YR requirement based on correction from Carlos

benchmarks/backwards_ecal/backwards_ecal.org

@@ -221,10 +221,11 @@ for clf_label, sigma_rel_FWHM_cb in sigmas_rel_FWHM_cb.items():
         lw=0.5,
         label=f"{clf_label}, ${np.ceil(stochastic * 10) / 10:.1f}\% / \sqrt{{E}} \oplus {np.ceil(constant * 10) / 10:.1f}\%$",
     )
-plt.plot(
+plt.fill_between(
     energy_values,
-    np.sqrt((1 / energy_values) ** 2 + (1 / np.sqrt(energy_values)) ** 2 + 1 ** 2),
-    color="black", label=r"YR requirement $1\% / E \oplus 2.5\% / \sqrt{E} \oplus 1\%$",
+    np.sqrt((2 / np.sqrt(energy_values)) ** 2 + 1 ** 2),
+    np.sqrt((2 / np.sqrt(energy_values)) ** 2 + 3 ** 2),
+    alpha=0.2, color="black", label=r"YR requirement $2\% / \sqrt{E} \oplus (1-3)\%$",
 )
 plt.title(INPUT_PATH_FORMAT)
 plt.legend()