Apply suggestions from code review

Co-authored-by: Francesco Pannarale <francesco.pannarale@ligo.org>

bin/pygrb/pycbc_pygrb_efficiency

@@ -613,7 +613,7 @@ if opts.exclusion_dist_output_file:
     excl_dist_dict['50%'] = excl_dist[50]
     excl_dist_dict['90%'] = excl_dist[90]
     with open(opts.exclusion_dist_output_file, 'w') as excl_dist_file:
-        json.dump(excl_dist_dict, excl_dist_file)
+        json.dump(excl_dist, excl_dist_file)
 
 # Plot efficiency using loudest foreground
 if opts.onsource_output_file:
@@ -642,15 +642,15 @@ if opts.onsource_output_file:
     ax.set_ylabel("Fraction of injections found louder than " +
                   "loudest foreground")
     ax.set_xlabel("Distance (Mpc)")
-    ax.plot([excl_dist[90]], [0.9], 'gx')
+    ax.plot([excl_dist["90%"]], [0.9], 'gx')
     ax.set_ylim([0, 1])
     ax.set_xlim(0, 2.*upper_dist - lower_dist)
     plot_title = "Exclusion distance - "+inj_set_name
     plot_caption = "Injection recovery efficiency using "
     plot_caption += "BestNR as detection statistic.  "
     plot_caption += "Injections louder than loudest foreground trigger.\n"
-    plot_caption += f" 90%% exclusion distance: {excl_dist[90]} Mpc\n"
-    plot_caption += f" 50%% sensitive distance: {excl_dist[50]} Mpc"
+    plot_caption += f" 90%% exclusion distance: {excl_dist['90%']} Mpc\n"
+    plot_caption += f" 50%% sensitive distance: {excl_dist['50%']} Mpc"
     fig_path = opts.onsource_output_file
     save_fig_with_metadata(fig, fig_path, cmd=' '.join(sys.argv),
                            title=plot_title, caption=plot_caption)