fix: show indicator when a song is an instrumental

lib/lyrics.dart

@@ -20,6 +20,7 @@ class LyricsPage extends StatefulWidget {
 class _LyricsPageState extends State<LyricsPage> {
   bool fetching = false;
   String? lyrics;
+  bool instrumental = false;
 
   @override
   void initState() {
@@ -35,13 +36,16 @@ class _LyricsPageState extends State<LyricsPage> {
     String path = widget.url.split('genius.com/')[1];
     String fullLyrics = '';
     if (await webScraper.loadWebPage('/$path?react=1')) {
-      webScraper.loadFromString(webScraper.getPageContent().replaceAll('<br>', '\n'));
-      var element = webScraper.getElement("div[data-lyrics-container]", ['data-lyrics-container']);
+      webScraper
+          .loadFromString(webScraper.getPageContent().replaceAll('<br>', '\n'));
+      var element = webScraper
+          .getElement("div[data-lyrics-container]", ['data-lyrics-container']);
       for (var section in element) {
         fullLyrics += section['title'] + '\n';
       }
       setState(() {
         lyrics = fullLyrics;
+        instrumental = fullLyrics.isEmpty;
         fetching = false;
       });
     }
@@ -82,6 +86,23 @@ class _LyricsPageState extends State<LyricsPage> {
                   ),
                 ],
               )
+            : instrumental
+                ? const Center(
+                    child: Column(
+                      mainAxisSize: MainAxisSize.min,
+                      children: [
+                        Icon(Icons.music_note, size: 50),
+                        SizedBox(width: 20, height: 20),
+                        Text(
+                          'This Song is an Instrumental',
+                          style: TextStyle(
+                            fontSize: 20,
+                            fontStyle: FontStyle.italic,
+                          ),
+                        ),
+                      ],
+                    ),
+                  )
                 : SizedBox(
                     width: MediaQuery.of(context).size.width,
                     child: SingleChildScrollView(