notifications.30s.py: add support for Discussions notifications

Problem

As-is the GitHub Notifications xbar script does not support opening Discussions notifications.

• https://xbarapp.com/docs/plugins/Dev/GitHub/notifications.30s.py.html

Solution

So, I've added a rudimentary way of opening repo Discussions, filtering the search to show the discussion with the correct title. You will have to click into it to read it.

This is less than ideal, but better than nothing.

How

1. add this near the top of def format_notification(notification): after the formatted = ... definition

    if type == "Discussion":
        formatted["href"]= notification["repository"]["html_url"] + "/discussions?discussions_q=" + urllib.parse.quote(formatted["title"])

2. add this image data for Discussions notifications:

    elif type == "Discussion":
        formatted[
            "image"
        ] = "iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAQAAAC1+jfqAAAAjklEQVR42qXMtUHFYBRA4Q/WyF5UlMgOuLtNFanYIm2kwi8Oz/WcX68Zz4rKW4+VFX80cvs9Fmp/hF297Ancq6yMKlhSqIcX/N3zFzRSGxKwbMeHMs1/wbpW2MK18G1rrWuSsOdauLNo4UNIbPxN8qIU7gCFE2z7n+RE6xDAhXBlTxjKnVB6MIIztVOT8A7rHFO4O8LaZAAAAABJRU5ErkJggg=="
        formatted["templateImage"] = formatted.pop("image")

To Do

• figure out the URL to open to the individual discussion directly

Open notifications.30s.py and inspect format_notification(notification), especially how existing notification types set href and templateImage. Verify a Discussion notification displays its icon and opens the repository Discussions search for the matching title; improving this to open the individual discussion remains a follow-up noted in the issue.