rustdoc: remove unnecessary DOM class h1.fqn

It's misleading. The main heading sometimes isn't an fully qualified name at all.

It's also redundant. It's always a child of `div.main-heading`, so just use that.

src/librustdoc/html/render/context.rs

@@ -639,7 +639,7 @@ impl<'tcx> FormatRenderer<'tcx> for Context<'tcx> {
                 write!(
                     buf,
                     "<div class=\"main-heading\">\
-                     <h1 class=\"fqn\">Rustdoc settings</h1>\
+                     <h1>Rustdoc settings</h1>\
                      <span class=\"out-of-band\">\
                          <a id=\"back\" href=\"javascript:void(0)\" onclick=\"history.back();\">\
                             Back\
@@ -677,7 +677,7 @@ impl<'tcx> FormatRenderer<'tcx> for Context<'tcx> {
                 write!(
                     buf,
                     "<div class=\"main-heading\">\
-                     <h1 class=\"fqn\">Rustdoc help</h1>\
+                     <h1>Rustdoc help</h1>\
                      <span class=\"out-of-band\">\
                          <a id=\"back\" href=\"javascript:void(0)\" onclick=\"history.back();\">\
                             Back\

src/librustdoc/html/render/mod.rs

@@ -364,7 +364,7 @@ impl AllTypes {
             }
         }
 
-        f.write_str("<h1 class=\"fqn\">List of all items</h1>");
+        f.write_str("<h1>List of all items</h1>");
         // Note: print_entries does not escape the title, because we know the current set of titles
         // doesn't require escaping.
         print_entries(f, &self.structs, ItemSection::Structs);
@@ -394,7 +394,7 @@ fn scrape_examples_help(shared: &SharedContext<'_>) -> String {
     let mut ids = IdMap::default();
     format!(
         "<div class=\"main-heading\">\
-            <h1 class=\"fqn\">About scraped examples</h1>\
+            <h1>About scraped examples</h1>\
         </div>\
         <div>{}</div>",
         Markdown {

src/librustdoc/html/render/write_shared.rs

@@ -345,7 +345,7 @@ if (typeof exports !== 'undefined') {exports.searchIndex = searchIndex};
             };
 
             let content = format!(
-                "<h1 class=\"fqn\">List of all crates</h1><ul class=\"all-items\">{}</ul>",
+                "<h1>List of all crates</h1><ul class=\"all-items\">{}</ul>",
                 krates
                     .iter()
                     .map(|s| {

src/librustdoc/html/static/css/rustdoc.css

@@ -139,7 +139,7 @@ h1, h2, h3, h4 {
 .docblock > h6:first-child {
 	margin-top: 0;
 }
-h1.fqn {
+.main-heading h1 {
 	margin: 0;
 	padding: 0;
 	flex-grow: 1;

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

@@ -526,7 +526,7 @@ function loadCss(cssUrl) {
         }
 
         let currentNbImpls = implementors.getElementsByClassName("impl").length;
-        const traitName = document.querySelector("h1.fqn > .trait").textContent;
+        const traitName = document.querySelector(".main-heading h1 > .trait").textContent;
         const baseIdName = "impl-" + traitName + "-";
         const libs = Object.getOwnPropertyNames(imp);
         // We don't want to include impls from this JS file, when the HTML already has them.

src/librustdoc/html/templates/print_item.html

@@ -1,5 +1,5 @@
 <div class="main-heading"> {#- -#}
-    <h1 class="fqn"> {#- -#}
+    <h1> {#- -#}
         {{-typ-}}
         {#- The breadcrumbs of the item path, like std::string -#}
         {%- for component in path_components -%}