content: clarify that "expand example" is clickable

Examples are collapsed by default, and if one clicks on the header, they
are expanded.

However, that's not terribly obvious to a new user, since the cursor
when hovering over those collapsed example headers is the default for a
text element, the "text selection" cursor.

Fix that, keeping the list sorted.

Change-Id: Idfb7baae1dfc3ae3b6800d58e0d95de49eabf1b7
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/241017
Reviewed-by: Julie Qiu <julie@golang.org>
diff --git a/content/static/css/stylesheet.css b/content/static/css/stylesheet.css
index 7bafc40..1135cd3 100644
--- a/content/static/css/stylesheet.css
+++ b/content/static/css/stylesheet.css
@@ -983,9 +983,10 @@
 }
 .Documentation-exampleDetailsHeader {
   color: var(--turq-dark);
-  text-decoration: none;
-  outline: none;
+  cursor: pointer;
   margin-bottom: 2rem;
+  outline: none;
+  text-decoration: none;
 }
 .Documentation .example-header {
   color: var(--turq-dark);