HtmlText.Truncate ignores invalid & sequences

Author: wiz0u

src/Telegram.Bot/Extensions/FormatExtensions.cs

@@ -277,8 +277,11 @@ public static string Truncate(string html, int count, string suffix = "…")
         for (; count > 0 && index < len; index++)
         {
             var c = html[index];
-            if (c == '&')
-                index = html.IndexOf(';', index + 1);
+			if (c == '&' && index + 1 < len && html[index + 1] is >= 'a' and <= 'z' or >= 'A' and <= 'Z' or '#')
+			{
+				int end = html.IndexOf(';', index + 1);
+				if (end > 0 && end - index < 10) index = end;
+			}
             else if (c == '<')
             {
                 int end = html.IndexOf('>', index + 1);

src/Telegram.Bot/ITelegramBotClient.cs

@@ -65,7 +65,7 @@ public interface ITelegramBotClient
 
 public static partial class TelegramBotClientExtensions
 {
-    /// <summary>Use this method to get basic info about a file download it. For the moment, bots can download filesof up to 20MB in size.</summary>
+    /// <summary>Use this method to get basic info about a file and download it. For the moment, bots can download filesof up to 20MB in size.</summary>
     /// <param name="botClient">An instance of <see cref="ITelegramBotClient"/></param>
     /// <param name="fileId">File identifier to get info about</param>
     /// <param name="destination">Destination stream to write file to</param>