lint: simplify code (gosimple)

Replaces infinite for loops containing a select on a channel with a
single case with a range over the channel.

Removes redundant assignments to blank identifiers.

Remove unnecessary guard clause around delete().

Remove `if condition { return true } return false` with return condition

Signed-off-by: Moritz Poldrack <moritz@poldrack.dev>
Acked-by: Robin Jarry <robin@jarry.cc>

lib/msgstore.go

@@ -452,9 +452,7 @@ func (store *MessageStore) Delete(uids []uint32,
 
 func (store *MessageStore) revertDeleted(uids []uint32) {
 	for _, uid := range uids {
-		if _, ok := store.Deleted[uid]; ok {
-			delete(store.Deleted, uid)
-		}
+		delete(store.Deleted, uid)
 	}
 }