rustdoc: merge background-image rules in rustdoc-toggle CSS

Author: notriddle

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

@@ -1512,6 +1512,7 @@ details.rustdoc-toggle > summary.hideme > span {
 }
 
 details.rustdoc-toggle > summary::before {
+	background-image: url("toggle-plus-1092eb4930d581b0.svg");
 	content: "";
 	cursor: pointer;
 	width: 16px;
@@ -1599,14 +1600,6 @@ details.rustdoc-toggle[open] > summary.hideme > span {
 details.rustdoc-toggle[open] > summary::before,
 details.rustdoc-toggle[open] > summary.hideme::before {
 	background-image: url("toggle-minus-31bbd6e4c77f5c96.svg");
-}
-
-details.rustdoc-toggle > summary::before {
-	background-image: url("toggle-plus-1092eb4930d581b0.svg");
-}
-
-details.rustdoc-toggle[open] > summary::before,
-details.rustdoc-toggle[open] > summary.hideme::before {
 	width: 16px;
 	height: 16px;
 	background-repeat: no-repeat;