Decode HTML entities in feed item titles

[bezin]

The RSS spec does not mention HTML in item titles. As Contao encodes HTML entities on input, they are currently output as is in the feed item title. This PR converts them back before outputting the title to the feed.

[ausi]

Do we need to do the same for the feed title and description here?

contao/news-bundle/src/Controller/Page/NewsFeedController.php

Lines 59 to 60 in e0c479f

	->setTitle($pageModel->title)
	->setDescription($pageModel->feedDescription)

And can we add a test case to NewsFeedControllerTest that ensures that special XML characters (<, > and &) are properly encoded?

[bezin]

For future reference:

• I decode HTML entities for feed title, feed description and each item title
• I do not decode HTML entities for each item description, as the RSS 2.0 spec specifically allows encoded HTML here
• I added a test case to check for correctly encoding < and > to prevent XML injections as requested by @ausi

[leofeyer]

Thank you @bezin.