* FeedExpander: Remove tailing content in XML
- Move preprocessing code into overridable preprocessXml()
- Auto-remove trailing data after root xml node
* FeedExpander: Add PR reference with use case
* FeedExpander: Code linting
* [FeedExpander] Keep content at end of document for now
Will add back later if more sites have the same issue
* [FeedExpander] prepareXml: Add type hints