Rollup merge of #43979 - Jouan:Add-links-for-impls, r=GuillaumeGomez

Add links for impls

Implements a solution for issue #23552
r? @QuietMisdreavus

src/librustdoc/html/static/rustdoc.css

@@ -445,6 +445,10 @@ a {
 .small-section-header:hover > .anchor {
 	display: initial;
 }
+
+.in-band:hover > .anchor {
+	display: initial;
+}
 .anchor {
 	display: none;
 }

src/librustdoc/html/static/styles/main.css

@@ -26,6 +26,7 @@ h1.fqn {
 h2, h3:not(.impl):not(.method):not(.type):not(.tymethod), h4:not(.method):not(.type):not(.tymethod) {
 	border-bottom-color: #DDDDDD;
 }
+
 .in-band {
 	background-color: white;
 }
@@ -83,6 +84,11 @@ pre {
 }
 
 :target { background: #FDFFD3; }
+
+:target > .in-band {
+	background: #FDFFD3;
+}
+
 .content .highlighted {
 	color: #000 !important;
 	background-color: #ccc;