Replace escaped quote string with quote character in MediaBrowser.Controller/MediaEncoding/EncodingHelper.cs

Co-authored-by: Cody Robibero <cody@robibe.ro>

MediaBrowser.Controller/MediaEncoding/EncodingHelper.cs

@@ -698,7 +698,7 @@ namespace MediaBrowser.Controller.MediaEncoding
 
             if (state.AudioStream != null && state.AudioStream.IsExternal)
             {
-                arg.Append(" -i \"").Append(state.AudioStream.Path).Append("\"");
+                arg.Append(" -i \"").Append(state.AudioStream.Path).Append('"');
             }
 
             return arg.ToString();