[FR]: Allow fetching feeds with Blank line before XML declaration

[DraconicNEO]

Brief description of the feature request

A common problem in many RSS feeds is a blank line before XML Declaration. Many feed readers are able to overcome this error and still display the feed. I think we should add the ability to read feeds that have this error in them as it is very common and doesn't really affect the data.

[martinrotter]

Please give URL to such a feed.

[DraconicNEO]

Please give URL to such a feed.

TheHardTimes' feed:
https://thehardtimes.net/feed/

[ScoobyDone]

https://blog.synology.com/feed - 1 blank line
https://georgerrmartin.com/notablog/feed - 2 blank lines

[martinrotter]

Fixed.