Add dogsheep source for Hacker News

Would also consider renaming this to hackernews

src/promnesia/sources/dogsheep.py

@@ -0,0 +1,28 @@
+'''
+Uses [[https://github.com/karlicoss/HPI][HPI]] dogsheep module
+'''
+
+from promnesia.common import Visit, Loc, Results
+
+
+def index() -> Results:
+    from . import hpi
+    from my.hackernews import dogsheep
+
+    for item in dogsheep.items():
+        hn_url = "https://news.ycombinator.com/item?id={item.id}"
+        title = "hackernews"
+        if item.title:
+            title = item.title
+        elif item.text_html:
+            title = item.text_html
+            if len(title) > 79:
+                title = f"{title[:79]}…"
+        loc = Loc.make(
+                title=title, href=(item.url or hn_url))
+        yield Visit(
+                url=hn_url,
+                dt=item.created,
+                locator=loc,
+                context=title,
+        )