Rollup merge of #91223 - GuillaumeGomez:headings-indent, r=jsha

Fix headings indent

Fixes #91200.

Screenshots with the fix:

![Screenshot from 2021-11-25 15-32-35](https://user-images.githubusercontent.com/3050060/143462481-f7e9ea13-72d5-46fe-90e0-9527e74599e3.png)
![Screenshot from 2021-11-25 15-32-49](https://user-images.githubusercontent.com/3050060/143462485-c010716a-0276-421b-a777-afff19c81c96.png)

If the first element of a top docblock is a heading, we still need to keep the indent, but only on this one (I added a test to check it). We need it because otherwise the anchor will go over the `[-]` toggle.

cc `@camelid`
r? `@jsha`

1 files changed, 6 insertions, 4 deletions

diff --git a/src/librustdoc/html/static/css/rustdoc.css b/src/librustdoc/html/static/css/rustdoc.css
index bfad5106951..479b5210f9e 100644
--- a/src/librustdoc/html/static/css/rustdoc.css
+++ b/src/librustdoc/html/static/css/rustdoc.css
@@ -1129,15 +1129,17 @@ h3.variant {
 	margin-top: 3px;
 }
 
-.docblock > .section-header:first-child {
+.top-doc .docblock > .section-header:first-child {
 	margin-left: 15px;
-	margin-top: 0;
 }
-
-.docblock > .section-header:first-child:hover > a:before {
+.top-doc .docblock > .section-header:first-child:hover > a:before {
 	left: -10px;
 }
 
+.docblock > .section-header:first-child {
+	margin-top: 0;
+}
+
 :target > code, :target > .code-header {
 	opacity: 1;
 }