rustdoc-search: use a throbbler with no motion

This change is a response to complaints about motion sickness.

Author: notriddle

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

@@ -2012,50 +2012,28 @@ a.tooltip:hover::after {
 	height: 34px;
 }
 
-.search-throbber::before,
-.search-form.loading::before
-{
-	width: 16px;
-	height: 16px;
-	border-radius: 16px;
-	background: radial-gradient(
-		var(--button-background-color) 0 50%,
-		transparent 50% 100%
-	), conic-gradient(
-		var(--code-highlight-kw-color) 0deg 30deg,
-		var(--code-highlight-prelude-color) 30deg 60deg,
-		var(--code-highlight-number-color) 90deg 120deg,
-		var(--code-highlight-lifetime-color ) 120deg 150deg,
-		var(--code-highlight-comment-color) 150deg 180deg,
-		var(--code-highlight-self-color) 180deg 210deg,
-		var(--code-highlight-attribute-color) 210deg 240deg,
-		var(--code-highlight-literal-color) 210deg 240deg,
-		var(--code-highlight-macro-color) 240deg 270deg,
-		var(--code-highlight-question-mark-color) 270deg 300deg,
-		var(--code-highlight-prelude-val-color) 300deg 330deg,
-		var(--code-highlight-doc-comment-color) 330deg 360deg
-	);
-	content: "";
-	position: absolute;
-	right: 9px;
-	top: 8px;
-	animation: rotating 1.25s linear infinite;
-}
 .search-throbber::after,
 .search-form.loading::after
 {
 	width: 18px;
 	height: 18px;
 	border-radius: 18px;
-	background: conic-gradient(
-		var(--button-background-color) 0deg 180deg,
-		transparent 270deg 360deg
-	);
-	content: "";
+	/* hourglass */
+	content: url('data:image/svg+xml,\
+	<svg width="16" height="16" viewBox="0 0 8 8" xmlns="http://www.w3.org/2000/svg">\
+		<g fill="none">\
+			<path d="m3.019 1.496v1.496l0.5878 1.018-0.5751 0.996v1.494" stroke="%233f3f3f"/>\
+			<path d="m5.003 1.496v1.496l-0.5878 1.018 0.5751 0.996v1.494" stroke="%233f3f3f"/>\
+			<path d="m2.006 1.5h3.978" stroke="%23000"/>\
+			<path d="m2.006 6.49h3.993" stroke="%23000"/>\
+		</g>\
+		<path d="m4.005 5.301-0.3987 0.6905h0.7977z" fill="%237f7f7f"/>\
+		<path d="m4.011 3.712-0.3987-0.6905h0.7977z" fill="%237f7f7f"/>\
+	</svg>');
 	position: absolute;
 	right: 8px;
 	top: 8px;
-	animation: rotating 0.66s linear infinite;
+	filter: var(--settings-menu-filter);
 }
 
 #search .error code {