Improve the loading screen error message

- Fix subtitle if the previously selected song had the same title

public/src/views/about.html

@@ -2,7 +2,7 @@
 	<div class="view">
 		<div class="view-title stroke-sub"></div>
 		<div class="view-content"></div>
-		<div id="diag-txt"></div>
+		<div class="diag-txt"></div>
 		<div class="left-buttons">
 			<div id="link-issues" class="taibtn stroke-sub link-btn">
 				<a target="_blank"></a>