Fix favicon media attribute

Author: davinotdavid

frontend/index.html

@@ -4,8 +4,8 @@
     <meta charset="UTF-8" />
     <meta name="viewport" content="width=device-width, initial-scale=1.0" />
 
-    <link rel="icon" href="/favicon.ico" media="(prefers-color-scheme:light), (prefers-color-scheme:no-preference)" />
-    <link rel="icon" href="/favicon-dark.ico" media="(prefers-color-scheme:dark)" />
+    <link rel="icon" href="/favicon.ico" media="(prefers-color-scheme: light)" />
+    <link rel="icon" href="/favicon-dark.ico" media="(prefers-color-scheme: dark)" />
     <link rel="manifest" href="/site.webmanifest" />
 
     <title>Thunderbird Appointment</title>