Improve readability

src/web/app/common/tags/url-preview.tag

-<mk-url-preview><a href={ url } target="_blank" title={ url } if={ !loading }>
+<mk-url-preview>
+	<a href={ url } target="_blank" title={ url } if={ !loading }>
 		<div class="thumbnail" if={ thumbnail } style={ 'background-image: url(' + thumbnail + ')' }></div>
 		<article>
 			<header>
 				<h1>{ title }</h1>
 			</header>
 			<p>{ description }</p>
-			<footer><img class="icon" if={ icon } src={ icon }/>
+			<footer>
+				<img class="icon" if={ icon } src={ icon }/>
 				<p>{ sitename }</p>
 			</footer>
-		</article></a>
+		</article>
+	</a>
 	<style>
 		:scope
 			display block