Raise heading levels.

Author: kpreid

src/librustdoc/html/static/js/main.js

@@ -1004,7 +1004,8 @@ function preLoadCss(cssUrl) {
             return;
         }
 
-        const allCratesHeading = document.createElement("h3");
+        // h2 puts this on the same level as the current crate name heading at the top
+        const allCratesHeading = document.createElement("h2");
         allCratesHeading.textContent = "Crates";
 
         const allCratesSection = document.createElement("section");
@@ -1029,7 +1030,7 @@ function preLoadCss(cssUrl) {
         for (const headingText of headings) {
             // Empty string denotes a group with no named heading.
             if (headingText !== "") {
-                const crateCategoryHeading = document.createElement("h4");
+                const crateCategoryHeading = document.createElement("h3");
                 crateCategoryHeading.textContent = headingText;
                 allCratesSection.appendChild(crateCategoryHeading);
             }

tests/rustdoc-gui/sidebar.goml

@@ -48,7 +48,9 @@ call-function: ("switch-theme", {"theme": "light"})
 assert-text: (".sidebar > .sidebar-crate > h2 > a", "test_docs")
 // Crate root has no "location" element
 assert-count: (".sidebar .location", 0)
-assert-count: (".sidebar h2", 1)
+// Crate root has two h2s, the second of which is the the crate list
+assert-count: (".sidebar h2", 2)
+assert-text: (".sidebar #rustdoc-modnav h2", "Crates")
 assert-text: ("#all-types", "All Items")
 assert-css: ("#all-types", {"color": "#356da4"})
 // We check that we have the crates list and that the "current" on is "test_docs".