Fix bugs in emote parser

src/Discord.Net.Core/Entities/Emotes/Emote.cs

@@ -66,15 +66,17 @@ namespace Discord
             result = null;
             if (text.Length >= 4 && text[0] == '<' && (text[1] == ':' || (text[1] == 'a' && text[2] == ':')) && text[text.Length - 1] == '>')
             {
-                int splitIndex = text.IndexOf(':', 2);
+                bool animated = text[1] == 'a';
+                int startIndex = animated ? 3 : 2;
+
+                int splitIndex = text.IndexOf(':', startIndex);
                 if (splitIndex == -1)
                     return false;
 
                 if (!ulong.TryParse(text.Substring(splitIndex + 1, text.Length - splitIndex - 2), NumberStyles.None, CultureInfo.InvariantCulture, out ulong id))
                     return false;
 
-                string name = text.Substring(2, splitIndex - 2);
-                bool animated = text[1] == 'a';
+                string name = text.Substring(startIndex, splitIndex - startIndex);
                 result = new Emote(id, name, animated);
                 return true;
             }