RSS Description Field Could Use a Space Where HTML not rendered

### Steps to reproduce

Okay this is hardly important...

1. Use a service like dlvr.it or ifttt.com to tweet content from a hypothes.is feed (testing https://hypothes.is/stream.rss?uri=http://dougengelbart.org/content/view/138/000/)
2. Tweeted version runs together the blockquoted selected text from original and the annotation (see https://twitter.com/DEngelbot/status/1093231108823539712) because the description wraps the selected text in escape HTML blockquote tags.

### Expected behaviour
It would be nice if there was a space or at least a ` ` after `</blockquote>`

### Actual behaviour
No space, when HTML is stripped in making a tweet, words run together

### Browser/system information
Not browser specific

### Additional details

Feed detail


When tweeted via one of these recipe sites, HTML stripped, and words run together