Set color for <a> in a more straightforward way

Previously, we set the default color for <a> tags to black, and then
had an override with a bunch of not() clauses to set anchors in
docblocks to blue.

Instead, we should set the default color for <a> to blue (or equivalent
in other themes), and override it for places like the sidebar or search
results, where we don't want them to be styled as links.

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

@@ -1079,10 +1079,6 @@ a.test-arrow:hover{
 	text-decoration: none;
 }
 
-.section-header a {
-	color: inherit;
-}
-
 .code-attribute {
 	font-weight: 300;
 }

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

@@ -214,18 +214,23 @@ nav.main .separator {
 	border: 1px solid #5c6773;
 }
 a {
+	color: #39AFD7;
+}
+a.srclink,
+a#toggle-all-docs,
+#source-sidebar a,
+pre.rust a,
+.sidebar a,
+.in-band a {
 	color: #c5c5c5;
 }
+.search-results a {
+	color: #0096cf;
+}
 body.source .example-wrap pre.rust a {
 	background: #333;
 }
 
-.docblock:not(.item-decl) a:not(.srclink):not(.test-arrow),
-.docblock-short a:not(.srclink):not(.test-arrow), .item-info a,
-#help a {
-	color: #39AFD7;
-}
-
 details.rustdoc-toggle > summary.hideme > span,
 details.rustdoc-toggle > summary::before,
 details.undocumented > summary::before {

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

@@ -174,23 +174,28 @@ nav.main .current {
 nav.main .separator {
 	border-color: #eee;
 }
+
 a {
+	color: #D2991D;
+}
+a.srclink,
+a#toggle-all-docs,
+#source-sidebar a,
+pre.rust a,
+.sidebar a,
+.in-band a {
 	color: #ddd;
 }
+.search-results a {
+	color: #ddd;
+}
+a.test-arrow {
+	color: #dedede;
+}
 body.source .example-wrap pre.rust a {
 	background: #333;
 }
 
-.docblock:not(.item-decl) a:not(.srclink):not(.test-arrow),
-.docblock-short a:not(.srclink):not(.test-arrow), .item-info a,
-#help a {
-	color: #D2991D;
-}
-
-a.test-arrow {
-	color: #dedede;
-}
-
 details.rustdoc-toggle > summary.hideme > span,
 details.rustdoc-toggle > summary::before,
 details.undocumented > summary::before {

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

@@ -169,23 +169,28 @@ nav.main .current {
 nav.main .separator {
 	border: 1px solid #000;
 }
+
 a {
+	color: #3873AD;
+}
+a.srclink,
+a#toggle-all-docs,
+#source-sidebar a,
+pre.rust a,
+.sidebar a,
+.in-band a {
 	color: #000;
 }
+.search-results a {
+	color: initial;
+}
+a.test-arrow {
+	color: #f5f5f5;
+}
 body.source .example-wrap pre.rust a {
 	background: #eee;
 }
 
-.docblock:not(.item-decl) a:not(.srclink):not(.test-arrow),
-.docblock-short a:not(.srclink):not(.test-arrow), .item-info a,
-#help a {
-	color: #3873AD;
-}
-
-a.test-arrow {
-	color: #f5f5f5;
-}
-
 details.rustdoc-toggle > summary.hideme > span,
 details.rustdoc-toggle > summary::before,
 details.undocumented > summary::before {

src/test/rustdoc-gui/anchors.goml

@@ -0,0 +1,17 @@
+goto: file://|DOC_PATH|/test_docs/struct.HeavilyDocumentedStruct.html
+
+// Set the theme to light.
+local-storage: {"rustdoc-theme": "light", "rustdoc-use-system-theme": "false"}
+// We reload the page so the local storage settings are being used.
+reload:
+
+assert-css: ("#toggle-all-docs", {"color": "rgba(0, 0, 0, 0)"})
+assert-css: (".fqn .in-band a:nth-of-type(1)", {"color": "rgba(0, 0, 0, 0)"})
+assert-css: (".fqn .in-band a:nth-of-type(2)", {"color": "rgba(0, 0, 0, 0)"})
+assert-css: (".srclink", {"color": "rgba(0, 0, 0, 0)"})
+assert-css: (".srclink", {"color": "rgba(0, 0, 0, 0)"})
+
+assert-css: ("#top-doc-prose-title", {"color": "rgba(0, 0, 0, 0)"})
+
+assert-css: (".sidebar a", {"color": "rgba(0, 0, 0, 0)"})
+assert-css: (".in-band a", {"color": "rgba(0, 0, 0, 0)"})