Fix DefaultFirefoxRevision comment (#1778)

Author: kblok

lib/PuppeteerSharp/BrowserFetcher.cs

@@ -64,7 +64,7 @@ public class BrowserFetcher
         public const string DefaultChromiumRevision = "884014";
 
         /// <summary>
-        /// Default Chromium revision.
+        /// Default Firefox revision.
         /// </summary>
         public string DefaultFirefoxRevision { get; private set; } = "latest";