[DevTools] Group options in network presets select.

Source/devtools/front_end/ui/helpScreen.css

Index: Source/devtools/front_end/ui/helpScreen.css
diff --git a/Source/devtools/front_end/ui/helpScreen.css b/Source/devtools/front_end/ui/helpScreen.css
index b7f5bd8e75cdbd7097f2b97c941ae2ee40ed076d..e930e874dce3ca768e8e914d458c58be4847c2c2 100644
--- a/Source/devtools/front_end/ui/helpScreen.css
+++ b/Source/devtools/front_end/ui/helpScreen.css
@@ -558,3 +558,15 @@ select.list-column-editor {
 .settings-developer-mode .settings-experiment-hidden {
     display: block;
 }
+
+.highlighted-setting {
+    animation: highlight-animation 5s linear;
+    animation-iteration-count: 1;
+}
+
+@keyframes highlight-animation {
+    0% { outline: auto 3px transparent; }
+    20% { outline: auto 3px rgb(255, 156, 0); }
+    80% { outline: auto 3px rgb(255, 156, 0); }
+    100% { outline: auto 3px transparent; }
+}