Use raw text instead of HTML for OpenProject bug details popover

Closes #38.

Note1: OpenProject supports markdown by default and the raw text will
include markdown formatting characters. This looks slightly less
aggravating than displaying the HTML code.

Note2: Input from the outside world is always considered unsafe and RPC
results are always HTML escaped due to security considerations. This
will always look not-right even if we render back to plain text!

trackers_integration/issuetracker/openproject.py

@@ -233,5 +233,5 @@ def details(self, url):
         status = issue["_embedded"]["status"]["name"].upper()
         return {
             "title": f"{status} {issue_type}: " + issue["subject"],
-            "description": issue["description"]["html"],
+            "description": issue["description"]["raw"],
         }