Rollup merge of #103088 - GuillaumeGomez:fix-settings-page, r=notriddle

Fix settings page

Thanks to #103060, I discovered that the settings page was badly rendered. This PR fixes it.

Before:
![Screenshot from 2022-10-15 16-02-41](https://user-images.githubusercontent.com/3050060/195990668-42e0b16b-3146-4864-b822-6f6a80fb77a5.png)

After:
![Screenshot from 2022-10-15 16-02-31](https://user-images.githubusercontent.com/3050060/195990664-20f967df-8989-4336-bca9-be52baab8e81.png)

r? ```@notriddle```

Author: JohnTitor

src/librustdoc/html/static/js/settings.js

@@ -216,7 +216,9 @@
         const innerHTML = `<div class="settings">${buildSettingsPageSections(settings)}</div>`;
         const el = document.createElement(elementKind);
         el.id = "settings";
-        el.className = "popover";
+        if (!isSettingsPage) {
+            el.className = "popover";
+        }
         el.innerHTML = innerHTML;
 
         if (isSettingsPage) {

src/test/rustdoc-gui/settings.goml

@@ -1,4 +1,5 @@
-// This test ensures that the settings menu display is working as expected.
+// This test ensures that the settings menu display is working as expected and that
+// the settings page is also rendered as expected.
 goto: "file://" + |DOC_PATH| + "/test_docs/index.html"
 show-text: true // needed when we check for colors below.
 // First, we check that the settings page doesn't exist.
@@ -140,7 +141,13 @@ assert-css: ("#settings-menu .popover", {"display": "none"})
 // Now we go to the settings page to check that the CSS is loaded as expected.
 goto: "file://" + |DOC_PATH| + "/settings.html"
 wait-for: "#settings"
-assert-css: (".setting-line .toggle .slider", {"width": "45px", "margin-right": "20px"})
+assert-css: (
+    ".setting-line .toggle .slider",
+    {"width": "45px", "margin-right": "20px", "border": "0px none rgb(0, 0, 0)"},
+)
+
+assert-attribute-false: ("#settings", {"class": "popover"}, CONTAINS)
+compare-elements-position: (".sub-container", "#settings", ("x"))
 
 // We now check the display with JS disabled.
 assert-false: "noscript section"