stop putting comments in the middle of call chains

`rustfmt` doesn't handle this very well.

src/database/key_value/rooms/user.rs

@@ -117,13 +117,13 @@ impl service::rooms::user::Data for KeyValueDatabase {
             self.userroomid_joined
                 .scan_prefix(prefix)
                 .map(|(key, _)| {
+                    // Plus one because the room id starts AFTER the separator
                     let roomid_index = key
                         .iter()
                         .enumerate()
                         .find(|(_, &b)| b == 0xff)
                         .ok_or_else(|| Error::bad_database("Invalid userroomid_joined in db."))?
                         .0
-                        // +1 because the room id starts AFTER the separator
                         + 1;
 
                     let room_id = key[roomid_index..].to_vec();

src/database/key_value/users.rs

@@ -828,9 +828,9 @@ impl service::users::Data for KeyValueDatabase {
         let mut last = prefix.clone();
         last.extend_from_slice(&until.to_be_bytes());
 
+        // Include last
         for (key, _) in self
             .todeviceid_events
-            // this includes last
             .iter_from(&last, true)
             .take_while(move |(k, _)| k.starts_with(&prefix))
             .map(|(key, _)| {