Rollup merge of #105739 - GuillaumeGomez:migrate-jump-to-def-link-to-css-var, r=notriddle

Migrate Jump to def links background to CSS variable

It's already tested in `src/test/rustdoc-gui/jump-to-def-background.goml`.

r? `@notriddle`

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

@@ -1071,6 +1071,10 @@ pre.rust .doccomment {
 	color: var(--code-highlight-doc-comment-color);
 }
 
+.rustdoc.source .example-wrap pre.rust a {
+	background: var(--codeblock-link-background);
+}
+
 .example-wrap.compile_fail,
 .example-wrap.should_panic {
 	border-left: 2px solid var(--codeblock-error-color);

src/librustdoc/html/static/css/themes/ayu.css

@@ -88,6 +88,7 @@ Original by Dempfi (https://github.com/dempfi/ayu)
 	--source-sidebar-background-selected: #14191f;
 	--source-sidebar-background-hover: #14191f;
 	--table-alt-row-background-color: #191f26;
+	--codeblock-link-background: #333;
 }
 
 h1, h2, h3, h4 {
@@ -154,9 +155,6 @@ pre, .rustdoc.source .example-wrap {
 .sidebar h3 a {
 	color: white;
 }
-body.source .example-wrap pre.rust a {
-	background: #333;
-}
 
 .result-name .primitive > i, .result-name .keyword > i {
 	color: #788797;

src/librustdoc/html/static/css/themes/dark.css

@@ -83,10 +83,7 @@
 	--source-sidebar-background-selected: #333;
 	--source-sidebar-background-hover: #444;
 	--table-alt-row-background-color: #2A2A2A;
-}
-
-body.source .example-wrap pre.rust a {
-	background: #333;
+	--codeblock-link-background: #333;
 }
 
 #titles > button:not(.selected) {

src/librustdoc/html/static/css/themes/light.css

@@ -80,10 +80,7 @@
 	--source-sidebar-background-selected: #fff;
 	--source-sidebar-background-hover: #e0e0e0;
 	--table-alt-row-background-color: #F5F5F5;
-}
-
-body.source .example-wrap pre.rust a {
-	background: #eee;
+	--codeblock-link-background: #eee;
 }
 
 #titles > button:not(.selected) {