js: Use ES6 object literal shorthand syntax.

Generated by ESLint.

Signed-off-by: Anders Kaseorg <anders@zulip.com>

static/js/settings_display.js

@@ -128,9 +128,9 @@ exports.set_up = function () {
 
         channel.patch({
             url: "/json/settings/display",
-            data: data,
-            success: function () {},
-            error: function (xhr) {
+            data,
+            success() {},
+            error(xhr) {
                 ui_report.error(
                     settings_ui.strings.failure,
                     xhr,