Also, fix bug where 'in_reply_to' never gets set.

Closes https://todo.sr.ht/~sircmpwn/lists.sr.ht/82.
---
 listssrht/blueprints/archives.py | 2 ++
 listssrht/process.py             | 1 +
 2 files changed, 3 insertions(+)

diff --git a/listssrht/blueprints/archives.py b/listssrht/blueprints/archives.py
index 7adc70b..cf2c385 100644
--- a/listssrht/blueprints/archives.py
+++ b/listssrht/blueprints/archives.py
@@ -76,7 +76,9 @@ def apply_search(query, terms=None):
     return search(query, terms, [Email.body, Email.subject], {
         "is": lambda q, v: q.filter({
             "patch": Email.is_patch,
+            "reply": Email.parent_id != None,
             "request-pull": Email.is_request_pull,
+            "thread": Email.nreplies > 0,
         }.get(v, False)),
         "from": lambda q, v: me_alias("From", q, v),
         "to": lambda q, v: me_alias("To", q, v),
diff --git a/listssrht/process.py b/listssrht/process.py
index 3e69544..f4b31c4 100644
--- a/listssrht/process.py
+++ b/listssrht/process.py
@@ -186,6 +186,7 @@ def _archive(dest, envelope):
     if parent is not None:
         mail.parent_id = parent.id
         mail.parent = parent
+        mail.in_reply_to = reply_to
 
     thread = mail
     while thread.parent_id:
-- 
2.23.0

Thanks! Applied your patch.