widgets: thread: Include Subject in MessageSummary

Replies to a parent message are not shown to avoid filling the buffer
with noisy repeating content.

Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

alot/widgets/thread.py

@@ -78,9 +78,17 @@ def _render_wrap(size, focus=False):
     def __str__(self):
         author, address = self.message.get_author()
         date = self.message.get_datestring()
+        subject = self.message.get_subject()
         rep = author if author != '' else address
         if date is not None:
             rep += " (%s)" % date
+
+        # Hide Subjects which are replies to the parent message.
+        # This allows threads containing multiple messages with distinct
+        # subjects to be displayed without adding noise to the replies.
+        if not subject.startswith(('Re:')):
+            rep += " " + subject
+
         return rep
 
     def selectable(self):