Make accessibility fixes

src/lib/Button.svelte

@@ -21,7 +21,7 @@
 	}
 
 	/* Disabled */
-	button {
+	button[disabled] {
 		opacity: 0.6;
 		cursor: unset;
 	}

src/routes/posts/[[page=integer]]/+page.svelte

@@ -46,14 +46,18 @@
 </ul>
 
 <div class="pagination-controls">
-	<Button disabled={data.page < 3} href={'/posts/'}><ArrowLineLeft /></Button>
+	<Button disabled={data.page < 3} href={'/posts/'}
+		><ArrowLineLeft aria-label="first page" /></Button
+	>
 	<Button disabled={data.page === 1} href={data.page === 2 ? '/posts/' : `/posts/${data.page - 1}`}
-		><ArrowLeft /></Button
+		><ArrowLeft aria-label="previous page" /></Button
 	>
 	<span class="current-page">{data.page}</span>
-	<Button disabled={!data.hasMore} href="/posts/{data.page + 1}"><ArrowRight /></Button>
+	<Button disabled={!data.hasMore} href="/posts/{data.page + 1}"
+		><ArrowRight aria-label="next page" /></Button
+	>
 	<Button disabled={data.page > data.pageCount - 2} href="/posts/{data.pageCount}"
-		><ArrowLineRight /></Button
+		><ArrowLineRight aria-label="last page" /></Button
 	>
 </div>